Regional Winners

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 was my first Viessmann vitocal air source heat pump installation on a project for an existing home that wanted to decarbonise. The building is a 1930s detached three-bedroom house with a 133m² floor area.

I’m particularly proud of this project because of the space we had to create under the stairs for the plant room and also because of how it has been running since installation. We are achieving at the moment a SCOP of 4.9, which means it’s running 490% efficient. For parity with gas for running costs, we have to be looking to achieve 3505 efficiency and we are well above that.

The main issue on this job was that the customer had a combi boiler so had no hot water storage. He didn’t want to lose any space in the upstairs rooms and the kitchen and utility had already been fitted out so we needed a different solution.

This led me to ask about the space under the staircase, it was in the hall and also backed onto the kitchen that currently had a bookshelf attached. After discussion, we decided to remove the bookshelf and see what space could be created, once we had removed the plasterboard and unearthed it under the stairs, I measured up and drew out what needed to be under there to see if it would fit. We then insulated, plaster boarded and skimmed the back wall and self-levelled the floor – we now had our plant room.

Once the above was done we then proceeded with the system design. The customer wanted to achieve the best-estimated efficiency that he could, so we conducted a full heat loss survey of the property to give us a room-by-room and full house heat loss. From here, I could look at sizing emitters, which in this instance were radiators – there was a total of 17 radiators to get to a 40°c flow temperature we needed to replace eight of them and add a second one in the lounge to meet the heat loss.

The radiators were replaced with all k3s, triple panel triple convectors rads. The next challenging part was the system design, I wanted to go with a direct open circuit system, meaning only one pump and a weather compensation curve dialled in correctly to achieve no less than design temperatures. The house does get a lot of solar gain on one side so we added TRVs to this part to limit these rooms on certain days. The only issue with this way of working is that the pump is already fitted so we can only work off the remaining head that is left from the factory, this is where pipe sizing becomes ever more important, with correct pipe sizing I was able to overcome the index resistance. I usually try to achieve .9m/s velocity but dropped it on this job so I could work with a lower pressure loss per m in the pipes to achieve a lower index.

Which products did you select for the job and why?

I selected the Viessmann vitocal 10kw 150-a for this job and a 200l oso geocoil cylinder.

I chose to only fit Viessmann boilers four years ago when I went self-employed because of the engine and build quality and because of how technically good and different they are from others on the market. I had been hoping to install a vitocal for quite a while but with it having an internal unit I didn’t have the space on any other jobs to make it work, which is the only ‘downside’ if you want to call it that for the vitocal. However, the internal unit provides quite a few features that are unique to the market.

This unique feature is a 16l defrost buffer, usually for a defrost cycle. Standard heat pumps will use heat from the system buffer or the house itself, which can sometimes cause issues with recovering the house temperature back. However, with the Viessmann defrost buffer this doesn’t happen.

The radiators I chose to fit were the ultraheat k3 radiators, I chose these because they have a unique feature (such as allowing you to pipe it top bottom opposite ends without piping it top bottom opposite ends ) we fit radiators with both valves at the bottom at opposite ends, this reduces radiator output, the ultraheat radiator allows you to take both valves into the bottom of the radiator but they are already piped internally as top bottom opposite ends, which raises the output of the radiators compared with the traditional UK method of piping them.

I chose primary pro for the insulation, internally and externally for the heating pipework. It has a very low thermal conductivity at 0° of 0.034 but it is also vapour and water resistant and waterproof. Once bonded and sealed correctly, there will never be an issue with water ingress into the lagging or heat loss from the pipework. Water ingress in lagging is a big cause of heat loss as the conductivity will rise greatly and soak the heat up like a sponge. Primary pro is also up resistant making it the perfect choice.

I also chose to use open energy monitor to monitor the performance of the heat pump with a third-party system. The viessmann software does allow monitoring but it’s only compressor efficient and doesn’t take into account pumping power. Pumping power is low, but constant and that will greatly change your cop or SCOP and is often overlooked. The use of third-party monitoring and including all energy use allows me to be sure I’m delivering an efficient system, not just an efficient heat pump. When we talk about system efficiency we should be talking about the whole system and what it costs to run every part of that not just how efficient the heat pump is.

What’s the point in having an efficient heat pump if your system is poorly designed and installed? The Oem kit I fitted consists of a flow meter, a wet pocket flow and return sensor and an internal temp and humidity sensor. This is then connected to the server and all information is stored there so you can see live data, anyone can log on and see this also if you choose to add it to the league table of installs. I find this a great way to see how the system is running but also a great way to see how it can be improved, since fitting this last July, my install has been near the top of the table and has been top for a long time. It has proven that there isn’t much more that I could have done on this job and has performed better than my expectations, the customer is also happy with how this is running and so is the manufacturer , Viessmann.

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

The project from start to finish including the pre and post-installation work with the heat loss and staircase work was 14 labour days, for the heat pump installation itself it was nine labour days. This project stood out just because of how it’s performing, with his solar PV coupled in with the air source heat pump, running this efficiently his house was self-sufficient for around 65-70% of the year last year, this was my client’s aim but it has gone way past what he had dreamt off.

I think I showcased my skills with the whole concept of the job, the plant room, the system design, the neatness of the lagging and pipework, allowing everything to be serviced, the layout and the way I used the space and most importantly how it’s running. MCS asked for a minimum of a 2.8 scop and, even during the cold spell in December, the system was running higher than that. In fact, at some points, it’s been in the 800% efficiency range. I told the client he could trust me to give him the system he wanted and I have repaid that trust by giving him what he wanted and much more.

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

The result has been that the customer has now achieved what he wanted in the form of:

• He has decarbonised and removed all gas from his home.
• His system is future-proofed for any new heat pump technology that arrives that is better than he has.
• His whole house is now comfortable 24 hours a day rather than just being on and off for periods and over and undershooting room temperatures.
• His energy usage has dropped.
• His bills have dropped.
• He has a heat pump system that will integrate with his solar pv or smart tariff if needed.
• From September last year we have used 2409kwh of electrical input and created 11942kwh of heat output which, in turn, is a SCOP of 4.96 that is a full 146% more than what we need to be comparable to a gas boiler, on a standard tariff and not taking into account the loss of efficiency on the gas boiler.
• We have a system that I can monitor remotely via the viessmann ViGuide app and also grant the customer access via the
• The customer is really pleased, he’s already passed me on to his neighbour who wants one installed, he’s also agreed to let the manufacturer, Viessmann, go out and film a case study on it.

We speak quite a lot via phone and email still, we have become friends.