| > Heat pumps don’t work well on old, poorly insulated houses in cold climates. If they can keep up, which is a big if, the price of electricity generally dwarfs natural gas, even if the heat pump is running at 250-300% efficiency. I've got a 1930s semi-detached house (UK, north of England) - heated solely by a ASHP for both heating and hot water. Our Seasonal Coefficient of Performance is currently 3.47 (347% efficient) - even if limit that to just last month (coldest month of the winter so far in the UK) our COP was 3.25 (325% efficiency). Roughly speaking if you can achieve a COP over 3.2x in the UK it should be roughly on a par with gas, assuming you go 'gas free' (i.e. you can make the saving on the gas standing charge). Personally we're running at ~£200 annual saving vs. my estimate of what costs would be for equivalent gas boiler - that's thanks in part to being able to do all our hot-water heating at night rates. House wise - we don't have cavity wall insulation, have 15+ year old double-glazing and probably should have more insulation in the loft (it fills the rafters but I think these days that's considered not enough). Also with changes to ECO (energy company obligations) and RO (renewables obligations) the differential between gas and electric will reduce further Anyhoo - added my example to show that ASHP can work perfectly fine in old, poorly insulated homes in (moderately) cold climates. ECO/RO link - https://www.moneysavingexpert.com/news/2025/11/energy-bill-c... |