One further thought @TrystanLea … ‘01 Running Costs’ addresses a key questions people have about heat pumps, very nicely.
Another key question is “will a heat pump keep my home warm when it’s cold outside?”. I wonder whether this question could also be addressed.
eg. For the coldest N day period over the last year, present the daily external & internal temps, maybe sub-divided into nighttime, daytime, evening. From the user perspective “I see a set of homes like mine maintaining 18-21c during the coldest days”.
Just a thought. Feel free to bypass 