Climate concerns and a desire to reduce carbon emissions resulted in the adoption of a heat pump and solar PV system into a detached house in York. The gas boiler in the property was coming to the end of its useful life and homeowner Mike Floyd wanted to take action to reduce the carbon impact of his home as a positive climate action for his newborn granddaughters.
Green Building Renewables (then trading as GoEco Renewables) supplied an Ecodan air source heat pump and Solar Photovoltaic (PV) 4.48 kW array for the project.
Air source heat pump (ASHP)
Green Building Renewables installed the Mitsubishi Ecodan 11kW air source heat pump (ASHP) just outside the house, with the heat pump water tank located in the first floor airing cupboard. Some single radiators were replaced with double fin radiators to help adapt the heating system from gas to heat pump.
Financial support for heat pumps
The project’s heat pump installation was eligible for the Government’s Renewable Heat Incentive (RHI) and is attracting an RHI payment of £333 per quarter over the next 7 years.
“The guide to applying that Green Building Renewables provided for signing up for RHI funding was excellent. I would encourage everyone to apply for the RHI scheme before it ends in March 2022 as it does help cover the costs of the initial outlay over time.”
Suitability for a heat pump
The 4-bed house was built in 2000 and so had reasonable insulation levels already. The insulation levels in the roof were further upgraded when Mike moved in, so the property was suitable for the 11kW output of the heat pump. Heat pumps operate at lower temperatures than conventional gas boilers so tend to need a greater radiator coverage to provide the right amount of heat. Green Building Renewables undertook a room-by-room heat loss calculation survey to ensure the system would deliver enough heat for the house. As a result, a number of the single fin radiators in the house were replaced with double fin radiators to accommodate this.
“Heat pumps work at a lower temperature output so initially you have to adjust to the more slow and steady way of heating your home. My thermostat is set to a constant 19 degrees Celsius and always feels comfortable.
Green Building Renewables offered an installation solution that created minimum post installation remedial works. Upgrading the radiators in the house was a relatively painless experience thanks to Green Building Renewables’ care and attention, meaning that no additional redecoration upgrades were needed.”
Green Building Renewables installed 14 solar PV (photovoltaic) panels of 320W capacity to the roof, which faces east and west. The electricity generated by the solar PV is used to power the electricity needs of the home including the ASHP, with excess being diverted to heat the hot water or exported to the grid.
The PV array is linked to an Iboost device (located in the garage) that sends surplus power to the domestic hot water immersion heater tank in the airing cupboard. When the hot water is up to temperature, any surplus power is then sent it to the grid, if there is no call from any other electrical appliances.
“The whole system is ace. The air source heat pump and solar PV work really well together. The solar PV system powers the heat pump in in daylight hours, providing free energy.”
Full data is not yet available but for the month of June 2021, the 4 bed house drew an average of 9kW hours a day from the grid, exported 398kW hours to the grid as well as providing off grid energy during daylight hours to heat domestic hot water and cooking, all for a billed cost of £12.39 for the month (41p/day).
“I have done some rough calculations and it looks like I’m getting around a 10% return on my overall investment, which is a lot more than I’d be getting if the money was sitting in the bank, with the added bonus of having substantially reduced the carbon footprint of the house.“
Great customer service and no ‘hard sell’
Mike Floyd shared his feedback on the company overall:
“I can’t praise Green Building Renewables enough! From the outset, the team were quick to respond. Harriet did the first site visit and gave me good honest advice without the ‘hard sell’. John advised me against having a solar storage battery and underfloor heating as not being suitable for my needs at this moment in time.
The installation team were superb. Any concerns were always handled well by the office team and although the install was staged over some months due to ASHP supply problems, all is now working well. The aftersales support has also been brilliant in dealing with any teething problems. An excellent team!
The COVID crisis was also handled by all the team members exceptionally well, always socially distancing and masked up.”
TrustPilot review (under former GoEco Renewables name).
Case study: 2021