Here is how we got our heat pump
This is a short piece on how we went about the changes we needed to make to ensure we were eligible for the boiler upgrade scheme (BUS).
Ideally, we would have got a ground sourced heat pump (GSHP), but it is much more expensive to do that once the house has been built. When we first made the decision to go heat pump, the recommendations were to get ground source to get a system with a reasonable/good seasonal performance factor (the multiplier of heat in the source to heat produced).
At that time, there was also a difference in how much money you got too – air sourced heat pumps (ASHP) were less efficient and you got less money!
Times have changed. Our ASHP returns a SPF of 5.7 during summer and 3.5 during the winter, giving an average of 4.15 (during the lifetime of our heat pump, we have consummed 3.97 MWh and enjoyed heat worth 17 MWh).
Yawn, and not giving me the details!
Sorry, it came down to understanding that we needed to ensure we were eligible for BUS. We mortgaged/owned the house and had a fossil fuel heating system, we had a gas central heating system to replace: two of the criteria successfully met.
We just needed the fulfill the last one: I needed to ensure our “property is suitable for a low carbon heating system.”
Heat pumps work a little different to fossil fuel boilers. Boilers tend to overheat water to send to your radiators and underfloor heating circuits.
That means working to reduce the amount of energy needed to keep the space warm and we worked to get our kWh/m2 down as low as possible. A “passive house” is rated at 60 kWh/m2, we’re at 64 kWh/m2, so we’re close. By comparison, a “new build house” is typically rated at 95 kWh/m2 and older house at 140 kWh/m2 . Your figure will be given in your EPC report.
By upgrading our room thermostats and radiator thermostatic values, we cut our gas requirements down from 15MWh to 12MWh. Which meant we could have a reasonably efficient single ASHP.
Having made those changes, (over quite a few months to spread the cost), I got evidence of the improvements and applied for a new EPC certificate.
To prove the “property is suitable for a low carbon heating system,” you need to score at least a Grade C EPC. Because the house was built to 2012 standards, our insulation was good enough (floor, walls, ceilings), our double glazing was good enough, etc. We also had fitted our solar cells in August 2014, with the solar diverter for hot water heating.
Because of our heating controls and LED lighting, we scored a Grade B off our original C.
The irritating thing, this time, was there were no recommendations given, as it was deemed too expensive to make changes to our house.
Which meant we applied to the company fitting our pump and claiming the BUS in late May 2024 and got everything sorted out for fitting with the BUS in that’s year’s mid-July.
You need evidence that your electricity supply box is good too – we had upgraded our electricity fuse box the year before to 2022 standards, so had all the paperwork available.
Can you sum that up, please?
Table below is the check list.
| Criteria. | Your status. |
| House owned or mortgaged by you. | |
| Using fossil fuel powered boiler, which you are completely replacing. | |
| Recent EPC ≥ C. | |
| Proof of wiring standard. | |
| Have an installer that is registered to make the claim on your behalf. |
Posted: August 30th, 2025 under Driving off the grid.