Our Experience installing a heat pump into a Grade 2 Listed stone house

Travellingwave · 2026-02-20T16:03:31Z

First want to thank everybody who has contributed to this forum (and the Open Energy Monitor Forum). I have pretty much learnt everything I need to know about heatpumps from reading the various topics on these forums. At the risk of repeating much of what has already been said - I thought I would add about our experiences with a heatpump in a property that theoretically is totally not suitable for one. We live in a stone house/cottage in North Yorkshire which has a total floor area of c 220 M2 with a recent garden room extension bringing it up to 240 M2 Being G2 Listed there are limits to what can be done in terms of insulation upgrades - the walls are solid stone approx 450mm thick with no cavity or insulation - Ground floors are solid and uninsulated, roof has an attic room with some fiberglass insulation between the rafters. Existing heating was oil fired - plus an oil fired AGA in the kitchen and a wood burner in the living room The EPC for the property is F and estimates an annual heat demand of 272 KWHr/M2 so c 60000 KWhr per annum Despite all of this we have found it to be comfortable to live in with the combined heating from the oil burner, AGA and wood burner. I would add that it was always clear that the EPC is a complete work of fiction since we never burned more than maybe 2500 litres of oil per year. Even with an old and inefficient oil boiler. We were both working so only heating part time. Around 2021 it became clear that the oil boiler was reaching the end of its life - baffles were burnt out etc so time to think about replacing it. I contacted some local companies about replacing the oil boiler and also about the possibility of a heatpump - from memory one company took one look at our EPC and told us no way would a heat pump ever work in this house , another company wanted to install 2 x 14 kw heatpumps which would require 3 phase supply to be installed , also had a quote to replace oil boiler for only a few thousand. Being an engineer by background I decided to do some experiments with the existing oil heating system to try to understand how much heat it was actually delivering and also to see how our existing system would cope with lower flow temps. I also took a lot of inspiration from the video on Youtube by Trystan Lee about his experience with installing a heatpump into an old stone cottage in Wales. I will continue story in next post.

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cathodeRay

(@cathoderay)

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23/02/2026 9:37 am

@jamespa — one of the big problems with historical oil consumption is you probably only have scrappy records (if that) of past oil deliveries that may not show any consistent regularity. There was a time when I tried to fill the ~1100L tank once a year in the summer when prices were lower, but that didn't always work out. The bottom line is the 1000L per annum is a very rough estimate. I certainly wouldn't bet my life on it!

We did discuss the oil to heat pump jump in apparent heat delivery some time ago in this thread. We didn't really reach a firm conclusion (i was still very new to heat pumps back then), more something along the lines that a lot of small things can add up, plus, crucially, the different use pattern, timed vs continuous running.

What I am reasonably sure about is that the overall picture (mostly my financial records are good enough to mean that i probably did include all oil purchases over the years, what is less clear is how and when the oil was used, and of course with the heat pump I have much better records) over several years is that energy delivered to the house did show a huge jump when I had the heat pump installed, and I think most of the explanation lies in the timed vs continuous heating pattern of use. My house probably did cool overnight and during the day when I used oil, I vaguely recollect it was only on for a small number of hours in the morning, and few more in the evening during the week, maybe more at the weekend. We were younger and fitter back then!

Midea 14kW (for now...) ASHP heating both building and DHW

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JamesPa

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23/02/2026 9:50 am

@cathoderay

Noted. In fairness some people only have scrappy records of gas consumption, its geeks like us that now keep everything!

Clearly if you dont have records and dont have much idea how the house was heated its going to be difficult. You still have an enormous increase in consumption however, you must have been living in something close to a freezer!

4kW peak of solar PV since 2011; EV and a 1930s house which has been partially renovated to improve its efficiency. 7kW Vaillant heat pump.

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cathodeRay

(@cathoderay)

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23/02/2026 9:57 am

Posted by: @jamespa

↑

you must have been living in something close to a freezer!

The years between oil use and the heat pump (roughly 2019 to 2021) when I used standard mains electricity to heat only the room(s) I was in were like living in a freezer in the colder months. The kitchen could get down to 7°C overnight. Maybe that put a rosy glow on the oil years, when in fact the oil years were also rather chilly at times. Plus as I said, we were hardier when younger!

Midea 14kW (for now...) ASHP heating both building and DHW

😂

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