Terrace property, hosted by Mat

Our house was build in 2004, with underfloor heating on the lower floor and radiators throughout the remainder of the property. After moving in in 2011, we changed the original Boiler in 2014 and after multiple costly services later (and a gas leak identified within the Boiler casing in 2022 after the Warranty had expired),  we decided to make the jump to a Heat Pump.

After much research in 2022 - 23, we opted for a Vaillant aroTHERM plus install by AIRA in October 2023. The install included a completely new heating system, with 9 correctly sized radiators throughout the property, a new slightly larger Hot Water tank (replacing the 2004 model), new zone valves and pumps, along with two expansion vesicles and a very small buffer header tank. We also opted to have two zones installed; one for the underfloor heating and one for the radiators. This does slightly effect the potential Coefficient of Performance of the system, but we requested this to unable improved control of the temperature within the house, where we opt to heat the home primarily via the underfloor heating, and only occasionally use the radiator zone for the 1st and 2nd floor of the Mews house property.

Our heat pump heated home makes for a very pleasant, comfortable space to live in. There’s no bursts of heat like you get with very hot gas heated houses, and the temperature is very consistent, even on the coldest days of the year, based upon maintaining set back temperatures.

Combined with the Cosy Octopus, heat pump specific tariff from Octopus Energy with off peak low cost use time (and high peak times to avoid), we’ve saved a significant amount of money. When comparing year for year use (gas and electric supplied home vs. just electric cut off from the gas main), our energy cost was 50% of the previous. This includes the annual cost avoidance of not paying a Gas supply Standing Charge (a cost avoided in perpetuity). 

Note that we have a solar and battery system, with the with the 16.5kW battery system (we retrofitted in 2021) enabling additional savings through purchasing all our daily electric at off-peak prices. In summer time, it’s worth mentioning the heat pump system has to do very little work, with no heating requirements and just to hot water to heat. When the outdoor air temperature is higher, the amount of heat energy in the air is greater, so creating hot water for a flow temperature set at 48 degrees (with once a week Legionaries cycle) uses a tiny amount of electric compared to deep winter. So much so, which our small solar array (installed in 2013, at 3kWp), our electricity usage is covered by solar production, and we purchase just £6.58 + standing charges from the grid for the whole of August. Compare that to a recent cold day, January 5th 2025, where it cost us £6.12 for just that day. As a result, our Octopus account ends up significantly in credit following spring, summer and autumn, with payments only exceeding the Direct Debit in winter and the fringe spring and autumn months.