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Shane Kosic

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Please tell us about a project you are particularly proud of – what was the problem and how did you solve it for the customer?

A project that really stands out as one I’m proud of is a heat pump installation that I completed for a customer in their home.

This installation really stands out to me because the customer had been attempting to have a heat pump installed in the new family home that they had purchased for four years. Over this time, they had requested several quotes from various companies, however, the customer said that they felt we were the only company that had actually offered them solutions to their worries.

When we first spoke to the customer, they shared their concerns about many aspects of the project, that they had also raised with previous companies they had sourced quotes from.

They were concerned about unprofessional installation practices, such as specifying buffers or additional pumps when not required. They also had plastic push fit pipework running throughout the house, which they were told would all need replacing, which was of concern to the customer.

However, upon developing the plans and calculating flow rates, I found that we could split the load between radiators fed from the loft area, and a flow and return going either way under the floor in the adjacent cupboard. This would be more than adequate to achieve our required flow rates, and this was proved upon commissioning when we had the required 1200LPH at 65% pump speed.

For this project, we carried out full heat loss calculations, drew up the designs and completed the full installation.

To make the installation effective, but without compromising the look of the home, we positioned the heat pump around the side of the property, running our primary pipework down the property in black trunking to look sleek and compliment the guttering and facias as best as possible. Externally we dug out the ground and laid a new concrete slab with a soak away for condense too.

Our primaries ran up and through the loft in Rubaflex insulation with a sealed edge and all joints taped with insulation tape to prevent heat loss as best as possible. The loft run was tricky so we transitioned to upsized multi-layer composite pipes (MLCP) so the flow through the MLCP was on par with 28mm copper. The customer had an existing solar thermal set up that he wanted to incorporate into the new design, this made the cupboard area very tight and we needed to make some adaptions on cylinder size to incorporate this.

Our 35mm MLCP primaries transitioned to 28mm copper and dropped down into the airing cupboard from the loft area. Into our Esbe valve, one side off to the cylinder and the other radiator feed coming off the Esbe in 28mm, teeing on into the loft in 22mm to feed three radiators. The other end passed through the cupboard next door, and into the floor where we found a passing flow and return pipe to tee into. This splits the rest of the loads each way.

We lagged all pipework in the cupboard with Rubaflex, and added butterfly valves to high points for maintenance with auto air vents, and made up a fill and flush point, rather than buying a purpose made valve as these are quite restrictive.

We filled the system with demineralised VDI water, and added a VDI top up unit for if the system needs recharging it can be done so without affecting the system water quality.

The customer is reporting great results so far, although it is early days, and we are tracking the systems performance on open energy monitor.

 

Which products did you select for the job and why?

For this project, we chose the Vaillant heat pump for its great performance, appealing looks and brilliant controls.

We chose an EBSE diverter valve rather than a spring-loaded valve as this had a better KV value and was more appropriate to deal with higher flow rates rather than a spring-loaded ball type valve.

We also chose an actuator head with a 15 second closing speed, which was the quickest we could get. We chose a faster closing speed so that when the hot water cycle was complete, it didn’t bleed heat to the radiators when the valve was turning and vice versa.

We also chose primary pro external insulation; because this made us confident our external pipework was fully sealed and resistant to water ingress.

Radiators come from a small independent supplier in Milton Keynes. They were a more expensive option but we were offered support because they’re local and I’ve been going since I was a kid going with my dad – a bit nostalgic but I want to keep them going as I trust them and they’ve never let me, or my customers, down.

I chose Valliant because they have the best controls in comparison to heat pumps on the market, generally good units with good performance and easy to control. Been fitting them for many years so I can tell their reliability and I can be confident in the job they’ll do – particularly in a newer market (renewables).  It’s also quiet to run too so means less disruption for the customer.

 

Tell us what was different or unique about this job? Why does it stand out?

This job had an awkward primary run, awkward pipework adaptions and a very tight cylinder cupboard for what we had to get in there and try to maintain pleasing aesthetics. However, this is one of the many retrofit installations we have carried out this year to very high standards. In total, this project took us 9 days to complete.

Each one of my retrofits is quite different and difficult but what stood out on this one was trying to figure out where to cut in and make the flowrate work. What made this job stand out was that we had a very particular customer who was very specific about efficiencies and performance from a system in plastic pipework. I had to find somewhere to tee in and split off the load so that we got the performance we needed.

I showed off my skills and experience by my adaptability and ability to design, plus my general pipework skills. Retrofits are harder than new build because you’re making the best out of the space and capacity that you have. I really put a lot of effort into the aesthetics of the pipework so it looks great.

 

And finally, tell us what the end result was for your customer?

The customer is extremely happy with the work, and this shows by their 5-star review, we have done all the fundamentals and more to take our installs to the next level, providing great performing systems with pleasing art in the form of pipework!

The customer was previously on a large LPG storage tank in the middle of their garden, and they now have a beautiful heat pump installation neatly tucked around the side of their home, we are expecting great results from this install and the customer will certainly be saving money and carbon!

I always keep in touch with customers when fitting heat pumps so I can make sure it delivering the performance they’re looking for. It’s early days on savings but the customer has been in touch to say how happy he is with the performance.

Liam Barry

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Please tell us about a project you are particularly proud of – what was the problem and how did you solve it for the customer?

The owner of this property was the former Head of Sustainability for HMRC, someone highly knowledgeable about energy efficiency and committed to finding the best possible heating solution for their home.

However, despite his expertise, he struggled to find an installer capable of delivering a system that met both his sustainability goals and the strict requirements of a Grade II listed building. After extensive research, he discovered my company through Open Energy Monitor, and we began developing a plan to upgrade his heating system while preserving the historic integrity of the property.

This project involved a Grade II listed house built in 1700, covering approximately 200m². Multiple installers had previously stated that the work couldn’t be done, but we took on the challenge. The property’s loft was completely uninsulated, so we explored all possible options and carried out insulation improvements to reduce heat loss. These improvements made it possible to install a heat pump, ensuring the building could be heated efficiently while preserving its historic integrity.

We installed a Viessmann Vitocal 150-A 16kW air source heat pump in a 400-year-old, Grade II listed timber-framed solid brick property with very limited insulation.

We conducted a full heat loss survey and determined that, with some secondary glazing and insulation upgrades, the property’s heat loss would be reduced to 13kW at -3°C. Using this data, I set to work designing a brand-new system.

Since the property was listed on the National Heritage List for England (NHLE), heritage authorities were fully involved in the project due to its age and protected status. We also undertook a full heating system re-pipe in this three-storey, six-bedroom home, installing new copper pipework throughout. To ensure the heat pump operated at peak efficiency, we carefully designed the system with correct pipe sizing and optimised flow rates.

Achieving the right flow is critical for system performance, maximising heat transfer and ensuring the heat pump runs efficiently across the entire home. By taking this approach, we delivered a future-proofed heating solution that meets efficiency standards while maintaining reliability and comfort for the homeowner.

As a listed building, we required permission for every aspect of the installation. We applied to install underfloor heating on the ground floor and designed it for a low-pressure loss under 20kPa, with a maximum flow temperature of 40°C.

Initially, we designed the first and second floors with standard panel radiators, but this was rejected due to the building’s listed status. As a result, we fully redesigned these floors using column radiators, ensuring a low-pressure loss of 25–32kPa, with pre-insulated 16mm MLCP and copper throughout.

Additionally, we incorporated a custom-built 250L Newark cylinder, which I helped design. Featuring 75mm insulation and a large 6m² coil running in reverse return, this setup delivered exceptional efficiency when recharging the hot water supply.

The entire system runs in a fully open-loop configuration with pure weather compensation, and it is actively monitored via Open Energy Monitor. Currently, it is operating at 500% efficiency.

 

Tell us about the products you selected for the job.

For this property, there was only one choice for me: the Viessmann Vitocal 150-A air source heat pump. I selected this unit due to its superior controls and one of the best in the market weather compensation technology.

As a Viessmann Pro Partner, I work with the best controls in the industry, ensuring precise temperature regulation and maximum energy efficiency. The unit features an integrated buffer tank, which correctly manages defrost cycles, improving reliability and efficiency. It also includes a backup heater, providing additional support in emergencies and assisting with defrosting in extreme weather conditions. Customers benefit from a 7-year warranty, offering long-term peace of mind. Viessmann provides outstanding service and technical support, which many other manufacturers lack. I also monitor system performance, and the Vitocal 150-A consistently ranks among the best-performing heat pumps on the market due to its high efficiency.

Also, the indoor unit houses a 4-way valve that effectively handles defrosting, along with an internal backup heater to support the building if temperatures drop below -5°C or in the event of an issue. We complemented this system with a custom-built Newark cylinder featuring 75mm insulation and a 6m² coil to maintain high efficiency.

The benefits of these products for the customer include high efficiency and improved comfort levels. The steady-state heating system in a Grade II listed house also helps with the building’s construction by drying it out and preventing damp and mould, significantly improving the customer’s living conditions.

 

Tell what was different or unique about this job? Why does it stand out?

As the property was grade two listed, this system took a lot of planning to get correct accuracy, along with a constriction on usable materials and products – as well as how we installed them (no holes in property etc).I was also told by the manufacturer that what I was planning to do with the open loop system via the Viessmann wasn’t possible. After doing calculations on the unit itself, I was very confident that the system I had designed was going to work and I was going to prove the manufacturer wrong – so putting everything on the line, I proved I could design a 16kw Viessmann open loop running off of one single pump in the unit.

What we had was lots of system volume a system designed to have an index circuit under 20kpa and full open energy monitoring system to show exactly how its runs. Currently running a flow rate of 35lpm with a pump speed of 85% and running at 500% efficiency, and the house maintains 20c through and hot water is set to 55c.

We designed a system with significant volume, maintaining an index circuit under 20kPa and integrating a full open-energy monitoring system to track performance in real time. The system currently operates at a flow rate of 35LPM with a pump speed of 85%, achieving 500% efficiency. The house consistently maintains an indoor temperature of 20°C, while the hot water system is set to 55°C.

 

And finally, tell us what the end result was for your customer:

The customer is very happy with the results and the system. After being told multiple times that a heat pump wouldn’t work in his home, he now has one of the highest-performing heat pumps to date. He also enjoys significantly reduced energy bills, which he further supplement with solar and battery storage. As a result, the owner is now highly active in promoting my company Customer Renewables.

We were fortunate to have a case study done for this project, and we have been highly commended at the National ACR and Heat Pump Awards 2025.

All performance results are available on heatpumpmonitor.org via Custom Renewables and Aylesbury, where the system is operating at 500% efficiency. The unit has been running on OEM, with a current SCOP of 4.2 in this Grade II listed property.

Craig Gilhome

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Please tell us about a project you are particularly proud of – what was the problem and how did you solve it for the customer?

Over the past year or so I’ve been working with a family who owned an old farm complex, and on the farm was an art gallery. The family knocked down the art gallery and, in its place, built a 4 bed, 4 bath new build, 350sq metre, 18 room property – very much a ‘Grand Designs’ project.

As the new house was on the site of a farm, there was lots of land, which enabled the homeowners – who had done a lot of research! – to opt for a ground source heat pump as the heat source for their new build. I worked on installing their heating and MVHR system.

This was an extremely high specification job, for a very knowledgeable homeowner, who only wanted to use the highest quality products. For me, it was a great opportunity to integrate different technologies together to achieve great building efficiency.

A consideration was that one of the future residents, for medical reasons, took a 40 min shower each day, which needed to run at 40°C. When I’ve been monitoring the system, it’s showing that around half of the energy usage is going on hot water, where usually this would be more around 20%. If it wasn’t for this, this property would be achieving even greater money savings, however it was crucial for me to listen to the needs of the homeowner and put a system in place that would work for their requirements. So, where it could perform better theoretically, I feel it’s current performance, based on this knowledge, is something to be proud of.

 

Tell us about the products you selected for the job.

The ground source collector was situated in a field in front of the new house. The homeowner had taken advice directly from a professor of energy modelling of the building environment, who has advised CISBE in the past. It made sense as they had the space to use. The ground temperature was 9.40°C and estimated ground thermal conductivity is 1.70 W/mK.

I chose a NIBE S1156 ground source heat pump and at the same time considered using it with the NIBE PV-T collector, which is an innovative heat source used with NIBE ground source heat pumps – it removes the requirement for a ground collector array and produces electrical energy that can be used to work a GSHP. However, I eventually just went for the heat pump as it was a huge field and due to the owner’s connections, I had access to labour to help dig!

I’d originally spec’d the NIBE 1155 GSHP, but NIBE had just launched the 1156 and it was an improved version – better refrigerant and improved controls.

I chose the manufacturer NIBE throughout where I could, as I wanted everything integrated – NIBE controls in the heat pump can control other accessories too (the MHRV units, extra climate systems, co sensors, and the zone temperature sensors). Via this app I can monitor the data too using the uplink, meaning I can keep an eye on the system for my client. The assumed SCOP is 5.02.

I ensured rigid ducting was used throughout and to avoid potential cross contamination of stale air, I left a min 2000mm clearance between the extract and outdoor air duct terminals.

In total there was around 800m of pipe in the ground with the collector split into 4 x 200m loops. This went into a manifold in the field, which I then fed underground, and under the house, to the plant room. I used 40mm collector pipe to.

The architect had chosen where to situate the plant room – which ended up getting smaller and smaller with not a lot of room in the end, but I got the job done.

For the MHRV system I chose 2 x NIBE ERS S10-400 units to supply ventilation, set up to extract from the kitchen, utility room, bathrooms, and supply air to the living areas and bedrooms. This has a high temperature efficiency up to 90% and low energy consumption.

I used a branch type system, not radial, because of the layout of the joist system, using plastic duct work. One unit serviced the ground floor, and one serviced the upper floor, and both were placed in the plant room. The client was extremely knowledgeable about MVHR and was very interested in the install – it’s given them fresh clean air and a nice luxury environment.

I split the system into two zones and used the NIBE extra climate systems to enable the mixing valves to mix the temperature to each different zone according to what the client wanted, all controlled by the central controller in the heat pump. The design flow temperature on the ground floor was 30°C and on the first floor it was 35°C.

For underfloor heating, I chose VPS, based in Glasgow. I’ve used them for years and trust them. It’s unbranded and they just offer a really good service. All manifolds, pipe and overlay board came from there too.

There were two UFH zones – ground floor and first floor. The UFH on the first floor was overlay onto a timber floor, with a 20mm board and 6mm of latex screed. The floor finishings were a mix of wood and carpet, so I calculated the heat loss based on the floor finish resistance, to make sure the different floor surfaces delivered the same temperature. For this I calculated the heat loss then the watts per square meter to calculate the heat released by each surface area. The ground floor was into screed with tile floor finish.

I ended up installing a 500l cylinder whereas usually I would have chosen a 200l model. This was because I calculated back from the number of litres per minute of water that would be required to ensure the shower stayed warm for the length of time required each day, at a temperature of 40°C. I didn’t want them running out of water as ultimately that would make the difference between a happy and unhappy client! The heating system was filled to VDI 2035 water treatment standards.

I fitted an IMI expansion vessel as in my opinion they are the best and most reliable vessels in the industry providing the customer with a product that will do its job without needing to be replaced for a long time.

All the pipe work in the house is pre-insulated M (Frankische) I have used this system for many years in high-end domestic new builds and find it the best solution, also the pre-insulated pipe work looks more professional and cuts down on distribution losses.

In the bathrooms, which were all high-end porcelain and marble, I fitted electric towel rails – there was no way they would get to the temperature needed to dry towels if hooked up to the rest of the heating system.

 

What was different or unique about this job?

When their architect drew up the plans, he hadn’t allowed for the requirements of the MVHR system, pipe work and soil and waste. When I first went in, I recommended the best/easiest solution would be to lower the ceilings to accommodate the pipework. However, the design of the building meant that dropping the ceilings wasn’t an option – one issue was that the windows were designed to work with the height of the ceiling for example.

I called two meetings between myself, the architect, the client, the timber frame manufacturer and the MVHR designer, where we looked at the design of the timber frame and worked out how to get the system fitted around the skeleton and joists. Each person drew their own plan up for their own area of responsibility, and we pulled these together to produce a solution. The building was timber frame, with steel supports, and using the CAD drawings we decided to run the pipework through the beams and within the fabric of the building.

On a practical level, this meant that when the products arrived on site, we would need to all co-ordinate to attend site and do our bit, and I was often finding I had to slide sections into whole assembled frames to allow the next parts of the build to continue.

 

What was the end result for the customer?

In summary a stunning, very efficient, home that works for their requirements and also saves on energy bills.

By fitting MVHR to the building the ventilation heat losses are reduced by up to 80% meaning the energy required to heat the building is less saving money for the customer long term.

From August 2024 to February 2025 the system has used around 2000kWh, which equates to around £400 in energy bills. The running costs would be a lot lower if the hot water demands weren’t as high, but these are still results I’m happy with.

The house also benefits from solar PV and battery storage (fitted by others) which means the clients energy costs are very low.

What I would add is that I’m now spending an increased amount of time monitoring data from different jobs I’ve done and learning from these. What I’ve observed is that insulation is making so much more difference to the heat system we installers fit. It’s now at the stage where it really is part of our responsibility to each client to advise on insulation levels – and how important it is (and where the easy wins are). Lots of people are oblivious but it has such as big effect on the performance of the systems we install. Fortunately, with this build, it’s something the architect had factored in, but in most situations it isn’t.

 

Joshua Bond

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Please tell us about a project you are particularly proud of – what was the problem and how did you solve it for the customer?

In February last year I was contacted by a client who needed his 1800’s cottage heating system brought into the 21st century. Firstly, to expand on bringing the house into the 21st century, the existing property had no central heating, the rooms had coal fires and the customer was using portable electric heaters to heat the rooms he was using. By bringing it into the 21st century we fitted modern double panel radiators in every room with thermostatic radiator valves, giving the customer a level of comfort, he hadn’t experienced before in this property.

This would be the biggest challenge that I have ever faced.

Not only was the Cornwall property old, it was large: a detached 8-bedroom stone cottage with draughty windows and doors. This property was riddled with damp and, ever since the customer purchased it, had never had a heating system that has heated it properly. The brief was simple. “I want the most efficient heating system that I can possibly have but I also want to be kind to the environment.” So, the planning began.

Months of back and forth, we joke the planning took longer than the job! The end result: X2 Hydrated vegetable oil boilers, X7 Zones of heating, X1 300 litre unvented hot water cylinder, x7 Nest Learning thermostats and more than 1 kilometre of copper pipe. It was sustainable because hydrated vegetable oil boilers are a plant-based bio-oil that are an alternative to using kerosene which is crude oil based. The sustainable option was recommended by us as the customer had not heard of HVO previously.

The decision to use HVO was made because the customer wanted to be environmentally friendly but the use of a heat pump with the heat loss of his house would’ve caused very high electricity bills and the electric in our area is still being produced with fossil fuels. We recommended HVO boilers to give the customer an efficient and environmentally friendly heating system.

 

Which products did you select for the job and why?

We chose to install Hydrated vegetable oil boilers for this job because the current house didn’t have the insulation needed to benefit from a heat pump. The client wanted to be environmentally friendly but knew a heat pump wouldn’t give him the efficiency needed from his electric bill point of view.

We installed Wilo modulating pumps to maximise the energy consumption. We installed Nest learning thermostats as they would start learning the customer’s temperature preferences from the day they started using it, which would help with the busy household’s schedule. This also means that the heating will not turn on when it’s not needed and the system would take into account the weather outside.

We installed automatic balancing valves to the return pipework to manage the flow rates through each zone. We sourced a boiler sequencing controller locally to manage when each boiler needed to fire.

If the demand was low, only one boiler would fire at a time and if the demand increased then x2 boilers would fire. We chose Wilo Pico central heating pumps because they modulate down to use less electricity when there is a lower demand. We chose the manufacturer, Wilo, specifically because of their reliability and efficiency.

We installed Worcester Greenstar Danesmoor utility boilers and converted them to HVO because of their reputation on being reliable and efficient. They came with a manufacturer’s 7-year warranty for peace of mind. All of the materials for this job were sourced locally from our local plumbing and heating merchant.

We chose Nest learning thermostats because of their sleek, modern appearance and are very user friendly. The customer liked the design and the ease of use. They take into consideration the weather outside to see if the boiler needs to be switched on and have the ability to learn your habits to predict when the heating needs to be on is a great benefit. All of these things encompass a truly efficient thermostat.

We installed a Warmworld BS2CO-2 boiler sequencing controller. We selected this model because it can control whether one or two boilers is needed depending on demand. For example, if there is just a hot water demand, there is no need for two boilers to fire and so the sequencing controller will just fire one boiler, however the more zones that call for heat, the sequencing controller will recognise this and act accordingly.

Using HVO as a heating fuel can significantly reduce carbon emissions in areas that do not have a mains gas connection, hence why it was chosen for this project. Buildings with low EPC ratings may need large investment into the building’s infrastructure to be suitable for alternative technologies. The boilers we fitted were kerosene boilers which we converted with a kit supplied by Worcester Bosch. This kit contained a nozzle, flame sensor and replacement isolation valve. HVO can reduce carbon emissions by up to 88% than traditional heating oil.

Due to being called Off Grid Plumbing and Heating Ltd our values are within renewable energy and decreasing the use of fossil fuels. The world is changing, so we are committed to pioneering ever changing renewable technologies.

 

Tell what was different or unique about this job? Why does it stand out?

This project was a real brain teaser. It encompassed all the skills that I have learnt over the years, from notching joists to an inch of tolerance to soldering pipework at an arm’s reach in tight areas. This project tested my plumbing knowledge to the core. It took 4 months to complete with a 1.5hour drive each way. It was a technically hard job but also a mentally hard job.

On this install I learned many things. I learned that you have to be able to trust the team that you have around you and rely upon others for their expertise in specific areas. I learned to time manage and prioritise. I learned how to plan and lay out system components on another level. I learned about the importance of communicating with the client and other tradesman to pull off a successful job.

 

And finally, tell us what the end result was for your customer?

The end result for this client was an energy efficient heating system install throughout his cottage. Every room reaching temperature quickly in the most efficient way possible. This client was very happy with the end result as were we.

Daniel Davies

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Please tell us about a project you are particularly proud of – what was the problem and how did you solve it for the customer?

I was particularly proud to be approached by a local high-end building contractor Williams and Thomas in Lampeter, Wales to design and install a system for their customer, that would provide the most efficient hot water and heating possible whilst offering ultimate comfort.

The property is a grand detached home, thought to have been constructed in the early 1800s, featuring seven bedrooms, four bathrooms, and three reception rooms, along with a snooker/games room. Additionally, a substantial extension offers a spacious kitchen and living area.  There was little in the way of modern insulation upgrades, and many of the windows and house fabric was original. There were large single glazed bay windows with 600mm thick stone walls spreading three floors with a total floor area of 315.89m². The building contractor was employed to build a substantial extension, measuring an impressive 80m² floor area, bringing the new floor area to 395.89 m².

Large roof lanterns measuring 5.53m² and south facing bifold windows covering most of the external wall needed more design considerations than usual. The main problem the customer had was integrating a highly insulated vaulted new build extension to a late 19th century, poorly insulated old building.

Due to the large renovation works on the north elevation of the building, we were faced with the problem of relocating the boiler and hot water system into the extension.

I met with both the building contractor and homeowner to discuss what they needed from the installation, before going away to design the system. I started with a full heat loss calculation of the existing building and extension. The property had a heat load of 30.19KW at -2.2˚ c. Due to extensive work carried out on the north elevation of the property, the customer asked if we could install underfloor heating in half of the ground floor of the existing house.

Once I completed the heat loss calculations on the building, I experimented with different flow temperatures to see what was the lowest flow temperature achievable with minimum upgrades. I discussed options with the customers. We decided to upgrade four out of twenty radiators which allowed us to reduce the design flow temperature to 60˚ c at -2.2˚ c ensuring the boiler would happily condense all year round. Some pipework was replaced mostly due to frost and corrosion damage.

The new build heat loss was done from plan and added to the overall heat load. Being highly insulated, the load was very small at 3.2 Kw. I explained to the customer that underfloor heating was the best option for different reasons. First was comfort; due to the high ceilings they would benefit more from the radiant heat transfer of underfloor heating over convection heat transfers from a radiator. In fact, the CIBSE design guide states that the majority of warmth is felt on the upper half of the body when using underfloor heating.

The underfloor heating pipe work was installed at 100mm centres so that we could achieve the room temperature with minimal flow temperature, saving energy and adding comfort.

After discussing my design approach with the customer, we decided that a heat pump was out of the question due to the capital cost of getting a three-phase electrical supply to the property to satisfy the heat load. We decided that a Viessmann 200W gas boiler was the best choice to satisfy the heat load of the existing build and the newly built extension – as this product is designed to prioritize hot water production while supporting two weather compensation mixed circuits to ensure maximum efficiency.

I suggested a priority hot water approach as the number of occupants living here would vary and we could size the boiler to the heat load.

The attic space where both the hot water and heating feed/expansion tanks were located was being converted to a new bathroom. Due to this I had to explore the possibility of converting both systems to a sealed system. I performed a pressure test on these two circuits and both passed. I was then satisfied that I could convert the heating to a sealed system and install an unvented hot water system.

I was proud to be part of this impressive project for a number of reasons and returning to the finished property six month later for our routine checks, with the family happily living in their newly renovated house, was the most satisfying thing to see. I was happy to see the installation working well and looking as new as the day we commissioned the system. Learning the importance of selecting the correct Kv value valve on this installation will be of huge benefit to upcoming projects.

 

Which products did you select for the job and why?

The heart of the installation was a 4 pipe Viessmann 200-w gas boiler. I selected this boiler for its impressive unmatched modulation and sophisticated controls that enabled me to have priority hot water and two mixed temperature circuits working independently on two heat curves. I really like the monitoring feature that Viessmann offers, this informs me of any issue on the system, in real time and often before the customers even notices a problem. The boiler, pipework and fittings were supplied by our local plumbing merchants, a two-minute drive from the job.

Immediately after the water leaves the boiler it travels through a Spiro vent. This vent is installed on the hottest part of the system to remove any air and micro-bubbles from the primary water. I fit this product on my installations because of its build quality and vital role in removing air, reducing noise, corrosion, unnecessary cavitation and noise in pumps. Tests carried out by “TNO en Kiwa GAS TEC**” claim that an installation can consume 6% less gas when a Spiro Vent is installed.

I needed to incorporate the old radiator heating system (originally being open vented at a DT of 10˚ c) to a brand new under floor system running at different flow rate (DT 5˚ c). I used the Flamco MeiFlow boiler guard to do this. This acted as a hydraulic separation to the boiler while providing air and dirt separation. Using this product, I knew that the boiler flow rates would be satisfied despite what happens downstream. The Flamco boiler guard comes in a highly insulated jacket that reduces unwanted heat loss.

I attached a Flamco distribution header to supply flow to both the new and original mixed circuits. The underfloor circuit is fed directly from the primary water while a Flamco plate heat exchanger pump set separates the old circuit water to the new VDI 2035 filled boiler and underfloor system. I decided to protect the new system from the old circuit for warranty purpose and to achieve best efficiency and to extend component working life. Both circuits now run on two separate weather compensated curves.

The intelligent boiler calculates the minimum flow temperature to supply to these circuits. The boiler constantly monitors the header temperature and both flow temperatures by means of a thermistor to calculate the flow temp it needs to supply. I requested that the Flamco pump-sets contained the correct Kv value mixer valves to satisfy each separate load. A mixer with Kv value of 3.18 for the underfloor circuit and Kv value of 13.4 for the radiator circuit.

I used the most basic of controls to promote system efficiency. Both circuits are controlled by pure weather compensation with no room influence. All this is achievable through the Viessmann PCB.

The 200L high gain Joule cylinder contains an impressive 18Kw heat exchanger. This can supply enough energy to re-load the cylinder to 45˚ c quickly keeping the stored temperature as low as possible to reduce standing heat losses. The Joule cylinder was used for its high performance, product quality and low standing heat losses. Using a thermistor over a traditional cylinder thermostat provides the boiler with far more accurate information and response times of milliseconds. The idea is to provide the cylinder with the exact amount of energy and no more.

I used Ivar under floor manifolds to supply 20 zones of underfloor heating. Manifolds were bought at our local plumbing merchants. These pipes had a maximum of 100mm spacings and are no longer than 90m long per zone. All zones were open loop with no thermostats just pure weather compensation. I have used various manifolds over the years however none compare to the reliability and build quality of the Ivar manifold. Having approximately 1300m of pipe in the floor ensures that the flow temperature is kept low which is no different to adding a huge radiator to a room. On top of this, an added benefit of this much pipe was the volume of water available to absorb excess energy at the boilers lowest modulation and reduce short cycling. This also future proofs the installation should a heat pump be required.

 

Tell us what was different or unique about this job? Why does it stand out?

The majority of our work is carried out on new build properties or complete renovations. So, having the opportunity to work on this project has been very different for us. The task of moving the plant room to make space for the alterations came with its own challenges. The only space we had was adjacent to the pantry so it was important that we reduced standing loses from our plant room to maintain a cool pantry. One way we did this was install the underfloor manifold in another location and kept all flows and stored temperatures low.

The gas supply to the original gas fires and cooker had to be calculated and re-routed due to the extensive renovation.

In this geographical area it is unusual to have a system completely controlled by weather compensation. I am the only installer in this locality that fits systems with weather compensation, with other installers favouring more traditional techniques. This project needed careful design as there would be an amalgamation of two systems and the old with the new. I wanted the systems to complimented each other and worked well for the customer.

I have also considered the possibility of adding a heat pump later and have up sized the primary pipework leading into the older building. Access will be very tricky in the future without cutting into ceilings. The unique difference to this job and what we normally do was the scale of both parts of the building and different heat loss to contend with. We were working with three different design flow rates, the original radiator system at a DT of 10˚ c, the new under floor heating DT of 5˚ c and finally the DT of the new Viessman boiler at 15˚ c.

This has been the biggest project that we have been part of in the past 12 months. I feel privileged to have worked on this project and working on such a beautiful, historic building has been such a pleasure and an experience I will not forget.

I have enjoyed the whole process from upgrading the water supply to moving the plant room into its new location in the extension. Knowing that I have carried out a successful install that is as efficient as possible gives me great satisfaction. Showing my ability to design, specify and install such a high standard installation has provided me with more exciting projects from the building contractors and has been a great confidence boost. I used the mass flow rate formula to determine my heating pipework sizes to achieve the correct velocities.

I showcased my skills by designing the whole system and calculating every part of the system and upgrading the old system where needed. I really enjoy planning and working out the correct specifications. Once the heating installation was complete, I then wired up all the controls and mixer valves, before commissioning. I take great pride in hearing that the customers have showed their friends and family the plant room when the living space is so impressive itself. I treat my installations as if it was my own home, they must look outstanding as well as outperform expectations.

From start to finish the plumbing and heating of the whole property was spread out over six months. I returned when needed for the building contractors.

 

And finally, tell us what the end result was for your customer?

Having such a large inadequately insulted property with high thermal mass, operating on time schedules and no thermostat was such an inefficient way of keeping warm. Replacing the original poorly modulating boiler with “on/off” controls for the best performing boiler on the market with the lowest modulation and weather compensated approach has not just saved energy, but added to the overall comfort of the individuals. The customer has the ability to have the older side of the property set to a “set back” temperature during low occupancy periods. The customers will spend the majority of their time in the new extension so having the older side at a lower temperature will add to their energy savings.

The customer is delighted to have live monitoring of their system and to be able to access to it from anywhere in the world. Having the ability to access the live monitoring as an engineer, I can explain to the customer if a simple fault such as low water pressure has occurred. I have designed the whole system so that a competent DIY customer can be confident in sorting any simple maintenance task without the need to call a heating engineer. I have provided the customer with a system that can provide the correct amount of energy at the right time without the risk of overheating leading to opening of windows and energy wastage; a modern approach to an old problem.

Stuart Sugden

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Please tell us about a project you are particularly proud of – what was the problem and how did you solve it for the customer?

One of the projects we are particularly proud of was the installation of a borehole ground source heat pump in a 300-year-old stone-built farmhouse in rural Scotland. This was a challenging but rewarding project, as it involved balancing modern renewable heating technology with the constraints of an old and historically significant building.

The farmhouse had four bedrooms and two bathrooms, requiring a system capable of meeting high heating and hot water demands for the family.

 

Why We Were Proud of This Project:

This installation demonstrated our ability to deliver a high-quality, future-proof heating solution while working within the complexities of an old property.

It showcased our expertise in ground source heat pumps and our ability to meet the 2025 Future Homes Standard ahead of time. We worked closely with our manufacturing partner to ensure the system was designed to provide maximum efficiency and comfort.

The project was particularly fulfilling because the homeowner was keen to switch to renewable heating but had serious concerns about whether their property was suitable. Seeing their confidence grow as we developed a solution tailored to their home was incredibly rewarding.

 

Challenges and Planning

The homeowner had struggled for years with high heating bills and an inefficient oil boiler, which failed to keep the house warm in winter. Their main concerns were:

• Heat loss due to the age of the property
• Minimising disruption during installation
• Ensuring the heat pump would work effectively with their existing heating system

 

To address these issues, we conducted a detailed heat loss assessment, which confirmed that while some insulation improvements were advisable, the property was still a good candidate for a ground source heat pump.

 

We worked with the homeowner to agree on a plan that:

• Used a borehole system rather than a horizontal ground array (due to limited garden space).
• Integrated the heat pump with large, low-flow temperature radiators to maintain comfort levels.
• Installed a buffer tank and smart controls to optimise efficiency and allow for future upgrades.

 

Technical Details of the Installation:

The 12kW ground source heat pump was selected to match the heating demands of the property. We drilled two 120m boreholes to extract stable ground heat, ensuring consistent performance even in the coldest months.

The system was designed to work at low temperatures (typically around 35–45°C flow temperature) to maximise efficiency. We upgraded the existing heating system with:

• High-performance radiators to improve heat distribution
• A 300L hot water cylinder to ensure a reliable supply of hot water
• Weather compensation controls to adjust the system automatically for seasonal changes

 

What We Learned:

This project reinforced the importance of thorough planning and open communication with the homeowner. It also highlighted how even old properties can successfully transition to low-carbon heating with the right approach.

By the end of the project, the homeowner reported lower energy bills, a more comfortable home, and the satisfaction of having a heating system that is both eco-friendly and future-proof. This installation set a benchmark for us, proving that historic homes can embrace modern sustainability without compromising their character.

 

Which products did you select for the job and why?

For this project, we carefully selected a 12kW Borehole ground source heat pump, a 300L hot water cylinder, and a range of high-performance radiators to ensure the best possible performance in a 300-year-old stone-built farmhouse. Given the challenges posed by an older property, every product was chosen with efficiency, reliability, and long-term sustainability in mind.

 

Why These Products:

The primary concerns for the homeowner were efficiency, running costs, and minimal disruption. We selected products that could provide:

• Stable and consistent heating, even during the coldest months.
• A future-proof system that meets the 2025 Future Homes Standard.
• Lower running costs compared to their previous oil boiler.
• Seamless integration with their existing heating setup while maintaining the character of the home.

 

Ground Source Heat Pump:

We chose a 12kW ground source heat pump from a trusted manufacturer known for high seasonal efficiency (SCOP > 5.0). This means that for every unit of electricity used, the pump provides over four units of heat energy, significantly reducing energy bills.

 

Compared to air source heat pumps, a ground source system was preferable because:

• It delivers a more consistent heat output due to stable underground temperatures.
• It operates quieter, which was important in a rural, peaceful setting.
• It requires less maintenance over time.

To extract heat, we installed two 120m Boreholes. This method was chosen over a horizontal ground array due to the limited garden space and to ensure minimal landscape disruption.

 

Hot Water Cylinder & System Components:

We installed a Gledhill 300L high-performance Indirect high gain hot water cylinder, specifically designed for heat pump compatibility, with large heat exchange coils for maximum efficiency. The standing losses of this tank are also some of the lowest in the market and so retains the heat preventing wated energy, to ensure the homeowner had a reliable and ample hot water supply. Unlike standard cylinders, this model has:

• Larger heat exchange coils, improving heat transfer efficiency.
• Optimised insulation, reducing heat loss and improving overall efficiency.
• Fast reheat times, ensuring hot water is always available when needed.

We also added a buffer tank to ensure smooth system operation, reduce cycling, and improve heat distribution, particularly for the low-temperature heating setup.

 

Radiators & Heat Distribution:

Since the property had limited space for underfloor heating, we upgraded the existing radiator system with oversized, low-flow temperature radiators. The existing radiator system was replaced with Stelrad K3 radiators, chosen for their high heat output at low flow temperatures, ensuring optimal performance at the low weather compensated flow temperature with the ground source heat pump. These radiators were specifically designed for heat pumps, offering:

• More efficient heat output at lower temperatures, making the system cost-effective.
• Even heating throughout the home, eliminating cold spots.
• A traditional aesthetic, blending seamlessly into the character of the farmhouse.

 

Sourcing and Local Benefits:

We prioritised UK-based suppliers to reduce carbon footprint and ensure strong after-sales support. The heat pump was sourced through our trusted manufacturing partner, known for rigorous quality control and long-term reliability. The hot water cylinder and radiators were also UK-manufactured, ensuring:

• Shorter lead times for installation.
• Easier access to spare parts if needed.
• Support for local businesses and sustainability in the supply chain.

 

What Makes These Products Stand Out:

Compared to alternatives, our selected products offered:

• Higher efficiency ratings, leading to lower energy bills.
• Longer warranties, giving the homeowner peace of mind.
• Smart controls and weather compensation, adapting the system automatically to outdoor conditions for better performance.

 

Final Results:

The homeowner now enjoys a warm, energy-efficient home, with significantly reduced heating costs and carbon emissions. By selecting top-tier products tailored to the property’s needs, we delivered a system that is both practical and future-proof, proving that even older homes can successfully transition to renewable heating. The homeowner’s annual heating costs dropped by over 50%, thanks to the heat pump’s SCOP at such low flow temperatures and smart controls.

Carbon emissions were reduced by approximately 3.5 tonnes per year, compared to their old oil boiler, making a significant environmental impact.

 

Tell what was different or unique about this job? Why does it stand out? What Made This Project Unique?

This installation stood out as one of our most technically challenging yet rewarding projects of the year. The property—a 300-year-old stone-built farmhouse—had significant constraints that required a bespoke approach to ensure the heat pump system delivered maximum efficiency while preserving the building’s character. Unlike many of our other projects, this one involved working within the limitations of an old, uninsulated structure while still ensuring compliance with modern energy efficiency standards.

 

Challenges and How We Overcame Them:

Unlike a new build, where insulation and heating design can be optimised from the outset, this project required us to work with:

• High heat loss due to the thick stone walls
• Limited space for a traditional ground array, requiring a borehole system
• A legacy heating system that needed careful integration
• Minimal disruption to the home’s original aesthetic

 

We conducted an extensive heat loss survey, calculating the property’s heating requirements to determine the correct size of the system. Instead of a horizontal collector, we opted for two 120m boreholes, which provided a consistent heat source with minimal impact on the landscape.

The process that we follow includes a room-by-room measurement to get the volume. How many external walls in each room. Discuss any insulation that has been upgraded.  Each window and door are measured, and its type and material noted. Existing radiator sizes are noted, and pipe work size also.

This allows us to check the existing radiators output at the new lower flow temperature and then look to upgrade for a similar sized radiator. For example, if the room is fitted with a 1000 single panel radiator and the calculations suggest that this is too small, we can then look at a double panel or even triple panel one to ensure we exceed the output required and save on decoration and mess in the house by matching the pipe centres for original radiators.

To overcome the challenge of low-temperature heating in an old home, we installed oversized radiators to ensure adequate heat output without requiring high flow temperatures. This was a key factor in making the system work efficiently in a property that was never designed for heat pump technology.

 

How We Showcased Our Skills:

This project required a high level of technical expertise and problem-solving, demonstrating our ability to:

1. Design a heat pump system for an older, thermally inefficient property while maintaining year-round comfort.
2. Drill and install a borehole system in a location with access limitations, ensuring minimal disruption to the customer’s land.
3. Work closely with the homeowner to ensure the installation met their expectations in terms of performance and aesthetic considerations.
4. Implement advanced controls to optimise efficiency, including weather compensation and smart heating schedules tailored to the home’s occupancy patterns.

 

Additionally, we had to coordinate multiple trades—from borehole drilling specialists to electricians and system engineers—to deliver a seamless installation with minimal disruption to the homeowner.

 

Project Timeline:

From initial assessment to final commissioning, the project took approximately eight weeks to complete. The borehole drilling itself took around one week, while the heat pump installation and system upgrades took an additional week.

 

One of the key successes was our ability to work efficiently despite the age and complexity of the building, ensuring the customer had minimal downtime and could continue using their home comfortably throughout the process.

 

Unique Location and Building Considerations The farmhouse’s historical significance and remote location made this project particularly interesting. Unlike urban projects where infrastructure is more accessible, we had to carefully plan logistics for equipment transport, drilling, and installation in a rural setting with limited access roads.

 

Furthermore, the home’s traditional aesthetic meant we had to be especially careful with pipework routing and radiator selection, ensuring that modern heating technology blended into the existing style of the property without compromising its charm.

 

Why This Project Stood Out:

This project showcased our ability to take on complex, high-end installations and deliver a heating system that not only improved efficiency and comfort but also proved that even older homes can successfully transition to renewable heating. The customer was thrilled with the results, and for us, it was a fantastic opportunity to demonstrate our expertise in overcoming unique technical and aesthetic challenges.

 

And finally, tell us what the end result was for your customer, for example, no more call outs, reduced energy bills:

The End Result for Our Customer At the end of this challenging but rewarding project, the homeowner was delighted with the transformation of their heating system. Before the installation, they had been struggling with an inefficient oil boiler, high running costs, and uneven heating throughout their 300-year-old stone-built farmhouse.

Now, they have a modern, low-carbon heating system that provides reliable warmth, significantly lower running costs, and a future-proof solution that meets upcoming efficiency standards.

Customer Satisfaction:

From the start, the homeowner was keen to switch to renewable energy but was unsure whether their old property could support a ground source heat pump. After seeing the result, they were not only relieved but incredibly pleased with how smoothly the system integrated into their home.

• They commented on how even the heating now felt throughout the house, eliminating cold spots.
• They were particularly impressed by the quiet operation of the system, compared to the noise of their old oil boiler.
• They appreciated the care and attention taken to preserve the aesthetic of their home, with pipework and radiators blending seamlessly into the original architecture.
• The homeowner was also pleased with how little disruption the installation caused, thanks to the careful planning and execution by our team.

 

Energy Savings and Running Costs:

One of the biggest concerns for the homeowner was the cost of heating their large, old property. Their previous oil boiler was not only expensive to run but also unpredictable in performance, often requiring costly maintenance. By switching to a 12kW borehole ground source heat pump, they have achieved:

• Immediate savings on fuel costs – Moving away from oil has freed them from the volatility of fuel prices.
• A highly efficient heating system – With a Seasonal Coefficient of Performance (SCOP) of over 5.0, the heat pump now delivers four times the heat output for every unit of electricity used.
• Lower maintenance costs – Unlike their oil system, the new installation has fewer moving parts and requires less maintenance over time.

 

Over the long term, these savings will only increase as energy prices shift and government incentives for renewable heating continue to expand.

 

Results of the Work:

After the installation was completed, we carried out extensive testing and optimisation, ensuring that:

• The system was operating at peak efficiency.
• The smart controls and weather compensation were set up correctly to adjust automatically based on outdoor temperatures.
• The hot water supply was consistent and met the family’s needs.
• The homeowner now enjoys a home that is:
• Warmer and more comfortable, with even heat distribution throughout all rooms.
• Cheaper to run, with significantly reduced heating costs.
• Environmentally friendly, with a substantial reduction in carbon emissions.
• Future-proof, meeting the 2025 Future Homes Standard ahead of time.

 

A Successful Transition to Renewable Heating This project is a perfect example of how even an older, historic property can successfully transition to modern renewable heating with the right planning and expertise. The homeowner now has a reliable, efficient, and cost-effective heating system that will serve them well for years to come.

For us, it was an incredibly satisfying project that demonstrated how ground source heat pumps can work effectively in challenging properties, and most importantly, it left the customer with a home that is warmer, greener, and more economical to run.

Max Smith

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Please tell us about a project you are particularly proud of – what was the problem and how did you solve it for the customer?

I was proud of this project because it gave me the opportunity to be on the cutting edge of renewable technology. I learned a lot about low temperature heating design in a house with an extremely low heat loss per m2.

The property was a large new build the property is 3099sqft, it has 4 bedrooms and 4 bathrooms, Passivhaus, as it is a requirement, with MVHR, Air source, Heat Pump and rainwater harvesting installed by me, and solar panels and batteries to follow. The MVHR was also a requirement, but would have been installed regardless.

The customer was unsure which direction to go in terms of heating and cooling the property, so I recommended the combination of a Stiebel Eltron WPL A-07 premium heat pump and Zendher climate switch MVHR. The MVHR unit is in the plant room, and has a 96% heat recovery, but will also supplement with passive cooling in the summer.

This was the first project on a full open loop design with no third-party components and ran completely off of one pump. We had to choose between an air source and a ground source but an air source was selected in the end due to the very marginal gains this type of property would get compared to the installation cost of boreholes for a ground source.

From the start, the customer allowed me to make all my own choices and do whatever I pleased. I had complete creative freedom with it as they just let me get on with the project and trusted my advice. Then, ultimately, they were very happy with the end result. I designed the system in such a way that the heat demand would be low, and flow temperature low. But the open system volume high for peak efficiency.

 

Which products did you select for the job and why?

The property had a 2.6kw heat loss. Because of this it was imperative a heat pump that could modulate down as low as possible was selected. The system was designed to be completely open loop, and the entire system is run off the single PWM controlled pump inside the bufferless HSBB 180 cylinder. The HSBB 180 cylinder was selected due to its PWM pumping capabilities which could cover the whole house off a single pump and maintain constant delta T.

The system was designed to 35-degree flow, however in usage the heat curve was able to be dropped lower than design and the temperature remained comfortable. The system is performing well since commissioning approx 8 months ago, averaging a combined COP of 5.96 at an average outdoor temperature of 11.7 (stiebel onboard monitoring). The project was a vanity project for me as a way to showcase my skills. By the time the solar panels are in, bills should be zero or negative and they can run almost entirely off the grid and sustainably.

Already they are almost there as the water is on a separate tank and uses rain water harvesting. I worked closely with the manufacturer from the beginning as they were able to give me recommendations on the specs needed for this project. The MVHR system was designed by the small specialist supplier Green Building Store and was installed by myself. The rainwater harvesting tank was in the back garden and was made up of a 3000 and 4000 litre harlequin tanks. The pump only feeds one outdoor tap for gardening and cleaning purposes.

The specialist supplier now wants to use my project as a case study for their website as they were so impressed with the end result. The heat pump and cylinder were all sourced from Steibel Eltron, the pipes all were purchased from local merchants and the water treatment system was from a local water softening equipment supplier, East Midlands Water. The underfloor heating was purchased from UFH1, and was designed to 35 degrees on a room-by-room basis, but I found I could actually run the heat curve closer to 0.2-0.3 and maintain comfortable temperatures.

 

Tell us what was different or unique about this job? Why does it stand out?

The reason this project stood out to me is that the build/installation was fundamentally focused on sustainability. All building materials were locally sourced, a percentage of the insulation used was made up of local hay bales and lamb’s wool, the heat loss and air tightness were kept to an absolute minimum to meet Passivhaus standards and ensure the MVHR could perform at its best. It further allowed me to demonstrate my best pipe fitting skills with a 28mm bender to keep flow rates high, and also get really stuck in with the design side of things and incorporating as many interesting products as possible.

I also fitted a rainwater harvesting system, and a small water quality improvement setup with a water softener and a silver impregnated carbon whole house filter. The water softener and carbon filter were from East Midlands water. This project was different from all my others as it was my first time working on a full passive house. I have had more since, but at the time, this was different for me. The project was a self-build so all in all, I was on and off the project for over a year, but the install on site took two and a half weeks. This includes the plant room and heat pump, all underfloor heating and two mezzanine radiators.

 

And finally, tell us what the end result was for your customer?

The customer was thrilled with the quality of all aspects of the installation and the comfort of the home as a result. The carbon usage is drastically reduced due to the reduced heat loss and renewable technology heating the property. No gas is used in the property, and water wastage is greatly reduced thanks to the rainwater harvesting system. I haven’t been back to the site since completion, but I have been able to keep on top of the heat pumps progress online and the SCOP score hasn’t dropped below 5.9 and the heat use tariff hasn’t dropped since the install. The house doesn’t need to be heat loaded if electricity is expensive you don’t have to heat the house and vice versa is electricity is cheap. I have been recommended to other developers thanks to the client, as they were a developer.

Damon Blakemore

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Please tell us about a project you are particularly proud of – what was the problem and how did you solve it for the customer?

In the past 12 months the project that stands out was a hybrid solution I presented for a client who had ongoing issues with 2 high temp Daikin air source heat pumps.

The project came to me because the customer had contacted an alternative heat pump manufacturer, Viessman, who I have worked with for years. Their team had been to site to look at the situation and conduct heat loss reports and knew that they needed an expert on renewables to take a look at the job. So, they recommended myself to the customer, and shared the project details and heat loss calculations with me.

The property is a 4-bed stone cottage set in its own land with no natural gas and the heat load / loss was around 16kw. The customer had got in touch initially with a view to repair the units: numerous engineers had been out, including the original manufacturer, Daikin, but had failed to sort the issues. After a couple of visits myself, and still no help at all from Daikin as the units were now obsolete, we decided to put a plan in place to renew the units the following summer to avoid any risk of the customer being without heat in the winter.

In the meantime, I made a few repairs and adjustments to the system to ensure that the customer wouldn’t be left without heat or hot water in the colder months. For example, the customer had 2 x 300L cylinders installed, which meant the heat pumps were struggling to heat the water efficiently, so we decommissioned one of the cylinders as he didn’t need both of them running all of the time and this was putting strain on an already poorly installed system.

The main problem was that a standalone heat pump wouldn’t cover the full load of the house, so, we needed a solution to be able to bring in a secondary source as a back-up that would also operate efficiently as a standalone heat source, in case there was any issues with the heat pump. The customer had already been through two Christmases without heating and hot water and didn’t want this again.

So, we agreed that would find a solution that would compromise of a bivalent hybrid system that would also provide heat and hot water if the heat pump was to ever fail.

The customer also had a solar thermal system that he wanted to be decommissioned and removed as it had never worked. He didn’t want to spend any money renewing it however, I advised that with a new pumping station I should be able to get this going again without renewing anything up on the roof: it just needed a bit of TLC. The customer listened to the recommendation and agreed that we should take a look at it in order to save costs later down the line.

Internally the house had UFH that had never worked properly, it needed a higher temp than the normal 50/55º as it had never been sized properly, so they were running very inefficiently and uneconomically. The solution needed to be a heat pump that could run at higher temperatures while at the same time still being quite efficient.

 

Which products did you select for the job and why?

In my opinion, with a hybrid system, we should be getting 80% of the heating load from the heat pump to make it worthwhile, the challenge here was to find the right balance with the right equipment.

My go to supplier is Viessmann because I think they have the best products on the market and a solution for nearly every application, plus they have viguide and vicare app built in which allows the customers to control all Viessmann products via an app and also allows myself to have remote access to see what is going on or to tweak anything, if needed. On a project like this, bit me and my customer thought this would be essential.

In this particular instance the manufacturer, Viessmann, didn’t have the off the shelf solution I required and only had two hybrids running in the country with the vitocal 150-a air source heat pump at this point.

The problem I had was that the 150-a heat pump wouldn’t take solar thermal nor would it allow a cylinder to be plate loaded, so I had to come up with design and specification that would work.

We would use a 16kw Viessmann Vitocal 150-a ASHP, which would give us 12kw at dot and then a 19kw Viessmann 100-w log system boiler, to help with the bivalent systems elm but also be capable of providing the full testing load in case of a heat pump issue.

The Viessmann solar thermal pump station would then be taken back to the 100-w which would allow it to be visible on the viguide and vicare app and give us some control over it so that we could see the generation.

We would use the 300l Viessmann cylinder and use the large bottom coil for the solar thermal, we would then plate load the cylinder from the heat pump, which is where it got tricky. What we did was use a pipe stat and a flow switch, so, as soon as the flow switch senses that the heat pump has gone into hot water it would power the pipe stand, and, as soon as that sees a rise in temperature, it would power the brass pump for the cylinder recharge. To date, this has been working very well.

What I then did also was utilise the four pipes on the on the system boiler and used the top coil on the cylinder so that if the heat pump failed and there was no solar thermal, the gas boiler could charge the top half of the cylinder so they had hot water.

This meant that every aspect of the brief was covered.

The Viessmann vital 150-a ASHP has a 8kw back up heater should the gas run out and the heat pump fail, and, we even installed a 5kw immersion in the cylinder as another element of insurance in the instance that everything else should everything fail.

The benefit here for the customer was that he was covered in every eventuality, it was all under one warranty with the manufacturer in case there was a need for repairs, and that the systems talks seamlessly to each other so he and I could both see it from our retrospective apps.

 

Tell what was different or unique about this job? Why does it stand out?

The uniqueness about this job was that we needed to cover so many outcomes for the client, which we eventually achieved.

It also stood out due to the fact that this was the first of its kind in the UK for the manufacturer, Viessmann’s, products and, coupled with this, the fact that there was no existing design for what I wanted to do. So, I had to start from scratch and design a completely unique solution myself to achieve what needed to be achieved. And, of course, it had to work.

In total, the project was completed over a two-week period.

The first stage was to decommission it all but leave the original hot water up and running, so that the customer wouldn’t suffer over the winter. We fitted the heat pump externally and then, in one day, swapped the cylinder across and got it back on the immersion so that they had water temporarily to the house. We had to work around the cylinder, which was challenging, but eventually we removed it and were able to fit it into position.

It also stood out because I had to use various skills to get it completed, not just from an installation point of view. The design aspect of this job was crucial and took everything that I have learnt and know to be able to have pulled this off, and not just to pull it off, but to get it to work effectively.

From an installation point of view, even though I had a bit of room, it was still a challenge to fit everything into the space I had, especially as I wanted to position everything in an accessible set-up to ensure that it could be easily serviced and maintained.

Finally, aesthetics was important here too. I wanted the job to look the part so I transformed the plant room into a nice area for the customer that he could also use as storage. This meant that, once the installation was complete, we plyed and painted the plant room to leave them with a pleasant space, as well as an efficient system that they could absolutely rely on.

 

And finally, tell us what the end result was for your customer?

Ultimately, he got what he needed: reliable heating on a bivalent system that will provide backup should the heat pump ever fail.

They will have hot water provided by solar thermal during the warmer months, with the heat pump picking up the rest of the load but, if there is any failure from other sources, the gas boiler will provide hot water. So, they have ultimate peace of mind.

The electrical back up also acts as a last resort to provide some heating and hot water.

Further to this, they also benefit from remote access for the customer and myself, so, any system alterations can be made and any issues that arise can be seen remotely. This will allow me to inform the customer that they need to do something, or that I am able to place the warranty call in a responsive manner without a site visit.

Currently, the heat pump is running at a scop of 3.5, which is still above parity with gas running costs, bearing in mind this is a high temperature system and is running 55c flow – so we are pleased. The current running costs are less than the old system.

I’d be lying if I said the job hasn’t been without a few hiccups. It’s something that hadn’t been done before so we were stepping into the unknown. Only 3 hybrids of this kind existed prior to this project, and none with solar thermal.

In fact, due to it being a genuine first-of-its-kind, of the back of this, the manufacturer, Viessmann, is bringing new updates to its software that engineers can go out and add via their computers. With this it brings changes to settings and additions of news ones which are there to improve how it runs and the operation of the system. More updates will come over time.

Ultimately, we created a system that works well now and is future proof – if the customer ever wanted to get away from the gas back up, we could add another heat pump as a cascade. If they ever added PV and battery storage then we will be able to incorporate this.

So, the installation is far from just a short-term solution, it was an investment in something that works well now and will only improve as time goes on.

Plus, it is covered for every eventuality which is what the customer needed.

Shaun Bone

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Please tell us about a project you are particularly proud of – what was the problem and how did you solve it for the customer?

I’m really pleased with the outcome of this project from design and planning through to the installation. The property is an old 1900s farm house in an exposed location and I was tasked with designing an efficient low temperature heating system (along with the rest of the plumbing works).

This is a large home is spread over 3 floors, with 4 bedrooms, 2 ensuites and 2 bathrooms, plus boot room, kitchen, snug, living room and office. I approached the planning by first evaluating the property and the heating options, focusing on sustainability, moving away from the existing oil boiler – as the customer wanted to future proof the property.

I did an evaluation on the property and pitched two ideas to the customer – a ground source vs air source heat pump system. Initially, the ground source pump was a fantastic option as this is a large property with land, so the customer had the space to complete the project. However, when I started to crunch the numbers, the figures put the customer off, so I instead went with the air heat pump option.

After completing the heat loss calculations. Which came in at 16.6 (as shown later in the entry) I recommended two 10 kw units as a master and slave set up.

The slave unit only comes on for the heating at an external temperature of 3 degrees.

I could of potentially fitted a 17kw unit but this would’ve been on the cusp and ran the risk of  struggling in colder weather (as shown by the heat loss calculalations) I went for a mixture of 150 mil and 100 mil centres depending on the calculations.

As it was a full refurb, we were able to install underfloor heating throughout which spans 3 floors. A couple of areas went in a screed and the rest was installed on an overlay system – in total we had 4 manifolds in the property.. As well as the UFH system, and the heat pumps, I recommended adding insulation across the property. For example, in both the snug and living room, there was no insulation under the suspended floor.  so 100mm kingspan was added between the joists.

All the external walls were insulated with 72.5 insulated plasterboard.

We just had the one pump serving the underfloor heating throughout the property. With the heating working strictly off weather compensation.

. We had 2 x 10kw grant Aerona heat pumps working as a master and slave. These fed into the buffer then we had a 42mm header and a Grundfos magna 1 32/120f pump serving the underfloor heating with 28mm to each manifold.

We had a variety of pipe spacing throughout the property to perfectly match the heat loss.

The customer insisted on thermostats but these are set at 23 degrees and just acting as limiters. The living areas sit around 21 degrees and the bedrooms around 19 degrees. The system has worked extremely well and the customer is more than happy with the outcome.

 

Which products did you select for the job and why?

I went for 2 x 10kw Grant Aerona heat pumps.

I went for Grant as I’ve installed a lot and I’m very familiar with the units and controller.

These were purchased from our local supplier Wolseley Plumb & Parts in Wolverton.

I then went for a World Heat hot water cylinder and a World Heat custom made buffer. These are made in Manchester. We then had a Grundfoss Magna1 32/120f pump serving the whole heating system. It’s a great pump and runs silently. I used Wunda for the underfloor heating as I’ve used them for years.

 

Tell us what was different or unique about this job? Why does it stand out?

This project was different and unique to all the others I’ve done as the property was an old 1900s farm house, in a rural exposed location outside of Milton Keynes. It just goes to prove that heat pumps aren’t just for new builds. It was quite testing from start to finish to make sure everything was absolutely spot on.

The project was testing due to a number of factors, the first being the different elements to the project – from consultation (ground source vs heat source), recommending additional measures for effectiveness (adding or upgrading insulation), decommissioning and installing the new heating system, fitting the plant room and the hot and cold-water system. Because of the size of the house, and as it was being completely gutted and renovated, I really felt as though I was project managing the works going on in the house.

The UFH system presented problems due to the property age and size, so we had to use an overlay system, sticking the boards and running the piping across the top, on all 3 floors – which naturally took up the bulk of the project.

The hot and cold-water system was a multi-layer mlcp pipe.

I had to ensure the insulation levels were up to scratch and worked with the builder on this, as I wanted to keep the heat loss down as  as possible – so was constantly going round the property checking the levels of insulation.

I’d like to add at this point, we re-piped the whole property.

The pipework in the plant room is where I could showcase my skills, I had many compliments which was nice. We started the project in January and completed it in July as it is a large property and the different elements to the project – the bathrooms, the hot/cold water system, UFH and heat pumps.

 

And finally, tell us what the end result was for your customer?

The customers were more than happy with the final outcome. They were keen to get rid of the old oil boiler and go for something green which we completed here. The heat pumps were a perfect fit for their budget. The house is nice and warm 24/7 and they’ve not had to adjust or touch anything.

They were eligible for the BUS grant, so they had £7,500 paid directly into their bank account.

So far, they’re spending less than they were on heating oil and there’s no reason why that should change.

My plan for this installation was to use the new grant smart controller which would’ve allowed remote monitoring but the launch date was pushed back till after the completion of the project. When it was finally released, it turned out it wasn’t compatible with a cascade system so while I cannot provide the SCOP, I can make an educated guess as I keep an eye on energy usage. My estimations make the SCOP of around 4 (or just under).

I was able to reach this conclusion because the heat loss report shows an estimated heating SCOP of 4.25 and hot water at 3.46 and a total yearly running cost of £3,117. Currently, we’re on track for a yearly running cost of £3,200-£3,500 calculated at £0.32 a kWH (the same as the heat loss report). This is estimated but imagine it to be quite close which is a great result.

It’s running a lot better than the previous oil boiler and even in the harsh, cold winter (-5 degrees!) which is a lot lower than the heat pumps are designed for, and the customer has had no issues.

 

Heat Loss Calculations:

Appendix M – Heat Pump Summary

SPACE HEATING

• Demand: 33,780.54 kWh/yr
• Heat supplied by HP (excluding auxiliary heaters): 33,780.54 kWh/yr
• SPF(2): 4.25
• Electricity consumed by HP (excluding auxiliary heaters): 7,948.36 kWh/yr
• Renewable heat supplied by HP: 25,832.18 kWh/yr
• Remaining heat to be supplied by auxiliary heaters and other heat sources: 0
• Electricity consumed by HP including auxiliary heaters: 7,948.36 kWh/yr

WHERE OTHER HEAT SOURCES ARE USED

• Fuel used: 0
• Efficiency of other heat sources: N/A
• Consumed by other heat sources: N/A

WATER HEATING

• of bedrooms: 4
• of occupants per bedroom: 1
• HP flow temperature in DHW mode: 55°C
• Hot water per occupant: 45 Litres/day
• Final HP secondary HW temperature: 50°C
• Demand: 6,340.05 kWh/yr
• Heat supplied by HP (excluding immersion heater): 6,205 kWh/yr
• SPF(2): 3.46
• Electricity consumed by HP (excluding immersion heater): 1,793.35 kWh/yr
• Renewable heat supplied by HP: 4,411.65 kWh/yr
• Remaining heat to be supplied by immersion heater: 135.05 kWh/yr
• Electricity consumed by HP including immersion heater: 1,928.4 kWh/yr

PROPORTIONS, ENERGY CONSUMPTION, AND PERFORMANCE

• Proportion of space heating and water heating demand provided by heat pump (excluding auxiliary/immersion heaters): 100%
• Renewable heat: 30,243.83 kWh/yr
• Electricity consumed by HP (excluding auxiliary/immersion heaters): 9,741.71 kWh/yr
• Electricity consumed by auxiliary/immersion heaters: 135.05 kWh/yr

RUNNING COST

• Cost per unit of electricity for HP: 32 pence/kWh
• Cost of electricity for HP (including auxiliary/immersion heaters): £3,160.56/year

Appendix K – Emitters and Performance

• Various details regarding underfloor heating types, floor surfaces, pipe spacing, and insulation types.

Appendix L – Fuel Comparison

• Comparison of heat pump efficiency against other heating sources.

Appendix H – Review of Heat Loss (Part 1)

• Breakdown of heat loss per room based on different factors such as windows, doors, walls, and roofing materials.

Appendix A – Summary of Results

• External Temperature Considered: -4.0°C
• Total Heat Source Required: 16.66 kW
• Heating Type: ASHP (Air Source Heat Pump)
• Manufacturer: Grant Engineering R32
• Model: Aerona HPID10R32
• Output at Design Temperature: 18.2 kW
• Max Flow Temperature: 45°C

Worst Performing Room:

• Room: Bedroom 2
• Floor Area: 17.93 m²
• Power Demand: 919.91 watts
• Specific Heat Loss: 49.51 W/m²
• Emitter Type: Underfloor Heating
• SPF: 4.25

Energy Calculation Method:

• • Based on worst-case scenarios, assuming all rooms are heated to their designed temperatures throughout the heating season.
  • Actual energy use may be lower as users typically do not heat all rooms simultaneously.

Liam Crossley

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Please tell us about a project you are particularly proud of – what was the problem and how did you solve it for the customer?

The project I would like to submit for the Heating Installer Awards is “Higher Giles Farm.”

This job came to my attention through a manufacturer’s (Polypipe’s) Approved Installer Scheme. I had previously worked with the client, repairing their heating system at their former property.

Upon purchasing the property, which is a five-bedroom converted barn that underwent several transformations in the early 2000s, the client sought my expertise for guidance. They were aware that two of the three boilers were over twenty years old.

We discussed the possibility of installing an air source heat pump with underfloor heating to enhance the unit’s efficiency. However, due to the remote location of the barn and advice from our electrician, we found that there was insufficient amperage to support the unit, barn, and all outbuildings on the land. Consequently, we considered reverting to the original heat source of LPG and completely overhauling the system to bring it up to modern standards.

With this in mind, I conducted a BTU calculation and recommended a full re-piping to connect two of the appliances due to poor system design and the use of non-barrier pipework. Unfortunately, the client had not budgeted for this, making it unfeasible. This situation left us with the challenge of managing a system with one non-functioning boiler and another that was quite outdated, both connected with non-barrier plastic piping.

After some consideration, I devised a comprehensive plan involving multiple pumps, several cylinders, and just one boiler this time. We agreed that relocating all equipment to a central location would be the most effective solution. I determined that the loft would be an ideal space to keep the heating system easily accessible at all times.

The plan was straightforward—at least I believed it to be. I intended to use a heat-only logic on a closed circuit with a Stuart Turner pump paired with an external plate heat exchanger to separate the non-barrier system, along with a Spirotrap expansion vessel and pressure relief valve. For the heating side of the system, I employed a Stuart Turner light commercial pump, two unvented cylinders in cascade due to the limited height available, multiple Honeywell zone valves, Hive home controls for user-friendliness, and a Honeywell frost thermostat for additional protection during the winter months.

Overall, this project tested my abilities. Coming from a background as a service and repair engineer for ten years, I initially felt out of my depth with such a complex system. However, after four years of running my own business, I now find myself setting the standard for quality and technical expertise while addressing issues that align with the client’s budget, all while keeping efficiency and reliability at the forefront.

 

Which products did you select for the job and why?

In every installation, my primary objective is to deliver the highest quality end product for my clients, ensuring they receive exceptional value for their investment. This project was no exception.

For the boiler, I selected the Ideal Logic heat-only boiler. I chose this particular boiler because I believe that, when properly maintained, it is one of the most reliable appliances available. Having installed hundreds of these units with only minor issues, I confidently recommend this brand. The manufacturer, Ideal, is well-established, producing over five million Ideal Logic boilers to date, and I take pride in endorsing their commitment to reliability and quality.

Regarding the system filter and expansion vessel, I opted for Spirotech products. Since the beginning of my career, I have advocated Spirotech products, as they exemplify quality manufacturing and provide superior water quality solutions. The extensive 20-year warranty they offer not only assures peace of mind but also reflects the confidence they have in their products. Their latest range of expansion vessels for domestic use is a pleasure to work with, showcasing a sleek design and excellent accessories.

When it comes to zone valves, Honeywell is the brand I trust. Established almost 100 years ago, their products are known for exceptional build quality, making them my preferred choice for installing zone valves in heating systems.

For pumps, whether they are booster pumps, shower pumps, or circulating pumps, I choose Stuart Turner. Their products not only perform exceptionally under demanding conditions but also have an appealing design, making them my preferred option.

In terms of cylinders, Gledhill stands out in the market, known for outstanding build quality and reliability, making them the ideal choice for safe and efficient water storage.

When it comes to copper tubing, I exclusively use Lawton products, which are fully recycled and manufactured in the UK. Their reliability and proven performance make them my preferred choice for all projects. All products for this project were sourced from our local suppliers at MKM Bury, located less than 10 miles from the site, ensuring prompt delivery and availability of materials when needed.

When designing a heating system, I always consider how to maximise its longevity and provide the best value for my clients. Beyond my expertise and experience, clients depend on me to deliver high-quality products, which is why I consistently choose to work with these trusted brands.

 

Tell what was different or unique about this job? Why does it stand out?

This heating project was particularly interesting and unique compared to others I have worked on, not only due to the complexity of the system design but also because of the challenges presented by the location. The system incorporated two Gledhill cylinders, an Ideal boiler, and an external plate heat exchanger, which served as a critical component in separating the two sides of the system, one being a sealed system and the other open vented. Each side was independently circulated using Stuart Turner pumps, ensuring efficient heat distribution while accommodating the structural limitations of the property.

The project took place in a barn dating back to the early 1900s, which introduced several significant challenges. Unlike modern buildings with predictable layouts and well-defined heating system compatibility, this barn had irregular construction, thick stone walls, and limited space for pipework. Retrofitting a modern heating system into a structure that was never designed for one required creative problem-solving and a deep understanding of heating principles.

One of the most technically challenging aspects was integrating the plate heat exchanger to separate the sealed and open-vented circuits. This was necessary to maintain system integrity while allowing efficient heat transfer between the two sides. The selection of pumps was also crucial; the Stuart Turner pumps had to be carefully positioned and calibrated to ensure balanced flow rates and avoid pressure-related issues.

Additionally, the system required meticulous air management, as the presence of both sealed and open-vented sections introduced the risk of airlocks. Through research and practical testing, I was able to fine-tune the system to operate smoothly, ensuring optimal performance and longevity.

Another factor that set this project apart was the need to work within the constraints of the barn’s aged construction. Unlike conventional buildings with standard joist and pipe runs, this barn had thick stone walls that made routing pipework particularly difficult.

I had to plan meticulously, often adjusting the design on-site to accommodate unforeseen obstacles. Through a combination of research, experience, and trial and error, I identified the most effective ways to install the necessary pipework without compromising the building’s structural integrity or aesthetic appeal.

My 15 years of experience in the heating industry proved invaluable in overcoming these challenges. The project demanded not only technical expertise but also adaptability, as unexpected hurdles frequently arose. By drawing upon my deep knowledge of system hydraulics, heat loss calculations, and component compatibility, I was able to create a heating solution that was both highly efficient and tailored to the unique demands of the property.

Ultimately, this project stood out because it required a high level of technical skill, problem-solving, and hands-on innovation. Unlike standard heating installations, where systems are often designed to fit within predictable parameters, this project demanded a bespoke approach, integrating modern heating technology into a historic structure with numerous limitations. It was a rewarding experience that tested and expanded my expertise, reinforcing the value of research, experience, and adaptability in achieving an optimal heating solution.

 

And finally, tell us what the end result was for your customer, for example, no more call outs, reduced energy bills:

The end result of this complex heating project was transformative for the client. From the outset, they were seeking a solution that would replace their outdated, inefficient heating system with something modern, reliable, and cost-effective. The installation of the new system, comprising two Gledhill cylinders, an Ideal boiler, a plate heat exchanger, and Stuart Turner pumps, achieved all of this and more, leaving the client genuinely thrilled with the outcome.

One of the most immediate benefits they noticed was the system’s responsiveness. The old system, consisting of two 20-year-old appliances, had been struggling to meet their heating and hot water demands. It was slow to heat, prone to breakdowns, and expensive to run. In contrast, the new setup provided instant, consistent heat throughout the property, with improved water pressure and flow rates. The client expressed how delighted they were to finally have a system that worked efficiently, especially in a property as challenging as their historic barn.

Beyond the noticeable improvements in performance, the client was also highly impressed by the level of craftsmanship and attention to detail that went into the installation. Retrofitting a modern heating system into a 1900s barn was no easy task, yet the final result was a seamless integration that preserved the character of the building while delivering cutting-edge efficiency. The client repeatedly commented on how much they appreciated the careful planning and problem-solving that went into the project, noting that my ability to adapt to the unique constraints of the barn was evident in every aspect of the installation.

From a financial perspective, the long-term savings were another major source of excitement for the client. Their previous system had been highly inefficient, consuming excessive energy and leading to unnecessarily high utility bills.

The new system, with its modern boiler, high-performance cylinders, and optimised heat distribution, was designed with efficiency in mind. By reducing energy waste and ensuring a well-balanced system, the client could expect significantly lower heating costs in the coming years. They were particularly pleased when I walked them through the expected savings, explaining how the improved efficiency would reduce their energy consumption and extend the lifespan of their new heating components.

Perhaps the most satisfying aspect of the project for the client was the newfound peace of mind. The old system had been unreliable, requiring frequent repairs and causing ongoing frustration. With the new installation, they could now enjoy a reliable, hassle-free heating system that provided comfort and efficiency without the worry of unexpected breakdowns. The fact that it was designed to be both low-maintenance and future-proof meant they could confidently rely on it for years to come.

In the end, this project was a resounding success, not just in terms of technical execution but also in exceeding client expectations. They were thrilled with how smoothly the installation went despite the challenges, and they expressed their gratitude for the expertise, problem-solving, and dedication that went into delivering a first-class heating solution. This project didn’t just modernise their heating system—it completely transformed their home’s comfort and efficiency, ensuring long-term savings and reliability for years to come.

Taylor Evans

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Please tell us about a project you are particularly proud of – what was the problem and how did you solve it for the customer?

My standout project of the year is situated in a small village on the outskirts of Cheshire. The property was one of two bespoke, new builds we completed, and they have been marketed and sold at £2,000,000. The house I worked on was 4 bedrooms and 5 bathrooms, one main, three ensuites and one downstairs w/c.

The specifications of the property and the standard that they needed to be were always at the forefront of any decision that I made down to a millimetre in difference of the thickness of the pipe, the distance of the pipework and so on.

There weren’t any major problems that had to be overcome except to make sure all our heating and hot water requirements were calculated as precisely as we could make them. The products we supplied needed to cover all the demands needed to carry out the heating and hot water specifications whilst being efficient and cost effective to the client.

Our company was brought in to fit the plumbing and heating by the developers Butler and Smith. They wanted us to do the job because we take pride in our work and that we were recommended by a few other people. The developers saw on our Instagram the other case studies that we had done in the past and knew we had experience in renewables. The developer builds projects to then sell them on.

We have worked on projects this big and bigger before, but this one was on the higher end of our past projects. This project came about by the developer seeing the high standard of work and other projects we’ve taken on. As well as us being very experienced in renewable heating. Originally the building plans were only for a ground floor and first floor but then the builders decided to include another floor with a bathroom. The developers added another floor because it was a dead space and a good opportunity, as it wasn’t hard to add another heating circuit to the system. We had to work out how to get heating up there and we had to add new circuits to compensate for the extra floor.

I learnt more about how important it is for the client to have clear and open communication. I used all my knowledge over the years to ensure that I supplied the best products for the job and to lay it all out in the best way to the client for them to make informed decisions, bringing together design and functionality.

It taught me how to deal with different demands and limited timeframes/scales. This was the best job the company had done, due to the complexity of the system being so different to the usual standard. It’s one of the best jobs we have done because of the expensive and high-end products we have fitted. Also, the flow of the job with no setbacks.

There was a lot involved with the heating system with so many manifolds with underfloor heating on both floors and with making sure the heat pump was able to take it on.

Heating and hot water both run off the Stiebel Eltron WPL25. The heat pump heats a 400ltr hot water cylinder to supply the main bathroom, master en-suite & 2 en-suite.

It also heats 100ltr buffer tank which is electronically mixed & feeds two floors of underfloor heating to maximise the efficiency. They are zoned and run at different temperatures for each floor with a thermostat in each room allowing it to be controlled more efficiently.

The project took eight months in total. The communication with the customer and I couldn’t be better, we had lots of open conversations, with constant updates. The customer came to site a lot and we would go through all sorts of changes, but he was happy with our work from start to finish.

 

Which products did you select for the job and why?

The products we chose are ones we are familiar with. We used a Stiebel Eltron WPL25 heat pump which is a 14kw unit. We used a heat pump instead of a boiler because it being a new property which is line with government guidelines and with us being a company with experience with heat pumps and renewables that we thought a heat pump would best fit these properties demands as well as no gas on the property. This supplied all the heating to the home and 400l of hot water.

We also had a 100l OSO stainless steel buffer tank which increases the system’s volume. The underfloor heating consists of five Emmeti manifolds; two on the first floor and three on the ground floor. The ground floor is mixed electronically to boost the efficiency of the install. Each room is controlled thermostatically using a Heat Miser Neostat V2, which can be controlled by an app on the end user’s phone. The underfloor heating sensors, that came along with the Stiebel EltronWPL25, went originally from 150ml to 100ml to counter the heat loss from all the glass and the height of the ceilings, also making it more efficient and easier to heat.

The heat pump is weather compensated, so it takes the outside temperature to give an ideal temperature indoors, thus again making it more efficient for the end user.

We use Stiebel Eltron as we know they are reliable; the parts are easy to get hold of the technical support is very good and our local team is excellent. One of their offices is only in Liverpool so not too far from us.

Their products can be remotely monitored by a Control4 Smart Home app on the new owners, which is a good selling point to installers and end users.

 

Tell us what was different or unique about this job? Why does it stand out?

The project took two weeks of planning, which I had been involved with since day one, deciding on the best layout and what sort of heating products went in. My role of the planning stage was more of the on-site fitting and managing the job on the tools and I was there for the following month on the install side.

The project stood out mainly because of the building specifications and how much attention to detail was focused on. I had to draw out and measure the space precisely before laying out pipe work to make sure there wasn’t any cross overs, and all pipes were equally spaced apart. Also, I had to make sure the pipework into buffers and pumps the dimensions were all the same and looking at specifications from manufacturers.

We always carry out our jobs to the highest level but this one really stands out as every detail was written down and discussed and checked over. I measured the distance between every pipe I laid to make sure spacing was exact even on things that won’t be seen.

I believe the nature of this job has showcased my skills and my attention to detail. Stiebel Eltron is doing a case study on the install as it impressed one of the regional managers. The second property was purchased from the look of the first one (this one).

Calculations:

The SAP rating shows as 84 B – at 84 it is just at the threshold of B (85-99). This should equate to 66 kWh/m2 pa = 19,998kWh. This converts to 9.1kW (2250 DD) and 30W/m2.

The walls, ceiling and floor are all new B Regs, but the U-values of the openings are better at 1.0 W/m2K, so overall better than new BRegs.

So, I would say the fabric is a bit better than those we use to get our benchmark 35W/m2. However, these are quite high ceilings so will need about 10% more than ‘normal’ – so I would still work on 35W/m2 = 10.6kW

 

And finally, tell us what the end result was for your customer?

The client was really pleased with the hard work I put in. They have gone on to sell it which they are happy about. They aren’t the end user but in the long run we are confident that they will see that their home runs highly efficiently and with low costs.

I feel that the client had trust in us, for us to execute their ideas and give advice and feedback when necessary, having an open and direct line to us at all stages (even on a Sunday evening!). Everything went to plan and in the time frame that we were given. They also then have a local team well placed to provide advice and guidance going forward.

We are currently in talks about a new development next door and were asked to work on the exact specifications on that property too. The customer was able to save money in the long run-on bills. The systems were implemented with weather compensation, meaning that they can read the temperature from outside to warm the house. It works off a heat curve, meaning even if it is minus degrees outside, it works at 50 degrees inside, but if it is slightly warmer outside, maybe 15 degrees, it may only need 20/30oc flow temperature indoors, therefore changing the temperature to suit the house.

The heat pump also has a summer mode setting, meaning that if the temperature outside is above 20 degrees, it will turn heating off as it knows the house is heated, and will therefore ramp up and down the hot water. Everyone that has seen this work has commented on the good work produced. The company and brand we worked for want to use this property as a case study and post it on socials as example for other customers and clients to see.

Jon Miles

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Please tell us about a project you are particularly proud of – what was the problem and how did you solve it for the customer?

This project has been a catalyst for the most exciting 12 months of my career to date. It has been recognised by the manufacturer, Viessmann, as an outstanding air source heat pump installation, and this has led to me meeting some of the best minds in the industry, including during a three-day trip to the manufacturer’s headquarters in Germany.

Since the new heat pump system started being monitored in July 2024, it has been steadily climbing up the HeatpumpMonitor.org leader board. With a SCOP of 4.55, it is currently the 15th best-performing system (out of 236) over the past 90 days, and I anticipate it reaching around 5.0 SCOP by the end of the heating season, which will put it in the top 5% of monitored systems.

As one of the first Viessmann heat pumps to be powered through the OVO Heat Pump Plus electricity tariff, the installation is breaking new ground as well as generating huge savings for the client.

The client, Mr & Mrs Hamad, had moved to rural Suffolk from London in early 2024. Their new home was originally a 1930’s two-bedroom bungalow with a 2019 extension and loft conversion added to make it a 5-bedroom property.

Although the Hamad’s had new radiators and a new underfloor heating network fitted, which were all installed to a high standard, the system was powered by an electric boiler which meant it was too expensive to run. To save money, the couple only used the upstairs radiators, relying on a log burner for warmth downstairs. I could see that a switch to a heat pump would make a big difference to both their running costs and day-to-day comfort levels.

The cavity wall insulation was confirmed using a camera and I was able to confirm the insulation levels in the inaccessible loft areas by removing some lights.

The installation was a great learning curve for me as it involved a very large number of U-value calculations as well as vaulted ceilings. Additionally, no plans were available for the underfloor heating, so this had to be verified using a thermal imaging camera.

I advised taking an open loop approach, removing all the zones from the underfloor heating and the zone valves to the radiator circuit. Although the client was initially sceptical about this, we settled on leaving the TRVs fitted to the two upstairs bedroom radiators for some comfort control if required. So far, this has not been necessary.

The system has a low design flow temperature of 35oC with an outside design temperature of -1oC. During the summer months The DHW target temperature is set to 52oC with a scheduled heat up at 2pm when the air temperature is highest.

During the heating season we have been opting for a lower store temperature and using hysteresis settings as the heat pump is running anyway.

 

Which products did you select for the job and why?

We opted for a 10kw Viessmann Vitocal 151-A air source heat pump with an integral 190-litre DHW cylinder for instantaneous hot water, as the compact and attractive units would give a tidy install. The outdoor unit was situated on the side of the property, visible from the road, so appearance was important. The indoor unit fitted snugly in plant cupboard. The 151-A also worked out to be slightly lower in cost than a Vitocal 150-A system with an external DHW cylinder.

The Vitocal systems are exceptionally quiet in operation, too, which made this a perfect choice for the peaceful countryside location. The 10w 151-A has a sound power level of 56 dB(A), similar to that of a fridge or microwave.

We installed and set up the heat pump to run full weather compensation with no room influence. As well as being very reliable and highly efficient, Viessmann heat pumps are widely regarded as offering the best weather compensation systems on the market, which makes them very efficient to run. They are also simple to operate either via a touchscreen or app, which make them popular with our customers.

As we are a local family run business ourselves; all kit used was purchased locally to support our local economy. This also meant it was able to be delivered using the minimum amount vehicle trips.

 

Tell what was different or unique about this job? Why does it stand out?

For me as an engineer, this project was the first time I threw the rule book away and put my Heat Geek training to full use. To ensure the installation would work within the capability of the circulator pump without a buffer, I had to do a full system schematic in H2X software. The heat loss was also completed in H2X as we had so many different wall U-values to calculate.

This was not SunLite Group’s first open loop or weather compensated system, but it was our first without any room influence. The results for the customer, in terms of cost-efficiency and comfort, have been exceptionally good.

Because of the high quality of the installation, it was selected by Viessmann to be given third-party monitoring equipment worth £950 in order to remotely track its performance, with the data published on HeatpumpMonitor.org [website].

We first began discussions with the Hamad’s in May 2024 and the installation took place over 5 days in June with the new system being commissioned on June 18th 2024. We returned in July to fit the open energy monitoring equipment.

 

And finally, tell us what the end result was for your customer?

The end result has exceeded all expectations. Since system monitoring began in July 2024, it has used 1968 kWh of electricity to generate 8940 kWh of heat. This means the running cost has been just £296, which is more than six times lower than the £1788 it would have taken to run the old electric boiler for the same period. Meanwhile, every room in the property is kept at the perfect ambient temperature at all times, which was not the case before.

The heat pump is barely audible when running against the low background noise of the quiet rural location, which is a bonus for the customer and their neighbours.

The Hamad’s are delighted with their new system “Very happy with the experience I received from Sunlite. They are quick to respond, friendly and helpful. Jon the engineer was very knowledge and provided an excellent service. Very happy with our new Viessmann air source heat pump and cylinder.”

We have since had 3 customer referrals from this customer all also opting for Viessmann products as well as support from them for other prospective customers.