Background
The house is approximately 18 years old, and previously had a standard gas boiler for heating and hot water. The rear of the house has an open plan area, which is a combination of the original kitchen and an extension that was added in 2006. The flooring in the extension part of the open plan area had electric underfloor heating, but the original kitchen and the rest of the ground floor and upstairs was being heated with radiators with microbore piping.
How we came to install the heat pump
We started with the intention to re-organise the use of the space in the open plan area at the rear of the house, and as part of that, replace the kitchen. During those works, the boiler would have needed replacing and relocating, and the electric underfloor heating would have ended up being destroyed as part of the removal of the existing tiled flooring.
As part of the remodelling, we initially intended to extend the underfloor heating across the whole of the open plan area at the rear, as previously, the transition from the warm tiles to cold tiles as you walked around was very noticeable during the winter, and just not very cosy! Alongside that, I was loathe to replace the existing boiler with another new boiler, as I wanted to do our bit for the climate and was keen to get away from burning fossil fuels.
As a result, I started looking into heatpumps and contacted three companies to come and talk to me about the feasibility and ultimately provide a quote. One company never got back to me, two came to have an initial chat, and ultimately only one properly engaged with me, but they were great from start to finish, and we’ve been very happy with the service they provided.
During the initial chat, we talked about the feasibility of using a heatpump and the options for the underfloor heating. I had learnt that water-based underfloor heating works well with heatpumps, but was concerned that doing this might require the floor height to be raised by 5-10cms. The contractor suggested the use of a low-profile insulated board (18mm) that could sit on top of our existing solid floor and then have a thin layer of screed poured across it once the water piping had been laid in the pre-cut grooves in the boards. We also talked to them about the possibility of extending the underfloor heating across the whole of the ground floor, which was very doable and indeed would provide a more efficient heating system for the whole house rather than keeping radiators in the other areas of the ground floor.
The contractor carried out a survey of the house and the existing radiators, organised for an EPC to be done and then designed the system and came back with a quote for supply and install of the heatpump, new water tank and all of the auxiliary heating equipment, as well as the underfloor heating. To give some context, the footprint of our ground floor is about 1400 square feet, with about half of this being the open plan area at the rear and the other half being the hall, office, lounge, utility, snug and toilet. The quote to supply and install a 16kW Midea R32 heatpump system with Heatmiser Smart control system came in at £16000, with an additional £12000 for the underfloor heating. The underfloor heating quote was split in two with the cost to do just the open plan area at the rear being about £7500, and an additional £4500 to extend it throughout the downstairs. The survey determined that there was no need to enlarge the existing radiators in order to adequately heat the upstairs.
In install was pretty much problem free, though was helped by the fact that it was being done as part of a remodelling of our downstairs. For instance, some of the plasterboard ceilings had been removed which made it easy for the guys to route pipework between the heatpump and the cupboard containing the water tank and other equipment. In total it took about a week and a half to install the heatpump system and all of the underfloor heating.
To date, the system has been absolutely fine and working well. It was only installed in April, and we weren’t back in the house until around June due to the ongoing works, so haven’t seen how effective it is through a cold winter as yet, but we recently turned the underfloor heating on with it now getting a bit chillier, and I immediately had to turn it down as it was getting too warm! The underfloor heating was designed such that each room is a separate zone controlled by its own wireless thermostat, and you can either use the thermostat in each room, or the Heatmiser app on your phone to set and monitor the desired temperature in order to optimise your use of the system and ultimately the amount of electricity that the heatpump is using.
Finally, we managed to get the system commissioned just in time to qualify for the RHI scheme, and again, our contractor was very helpful, talking me through how to complete the application, which resulted in a grant of about £10500 which is payable quarterly for the next 7 years.
We’ve subsequently had our gas meter removed, and with our electricity coming from renewables, we are now fossil fuel free. The only trouble is that we’ve now got the ‘sustainability’ bug and need to save up for some solar and battery storage!
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