> which I think google dimensional analysis tells me is $.0644/kWh for gas? Which is GBP 0.053/kWh for gas? Double what you are paying?

You're paying about half of what I am for gas and electricity, almost 1/3 of the unsubsidised price. I'm paying GBP 0.1028/kWh for gas and electricity is GBP 0.3376/kWh. We usually list energy in pence(£1/100) as it's a bit easier to read.

It's interesting that you have additional consumption based supply charges. We have an additional daily "standing" charge that's independent of use. Currently those are GBP .2256/day(GBP 93.294/year) for gas and GBP 0.4669/day(GBP 170.4185) for electricity.

> Hm, so OP is suggesting at these prices heat pumps should still work out, which is not what you found...

The ratio between electricity/gas prices has reduced since I last looked into it. Based on 2020 energy prices in the UK a heat pump would have been more expensive to run unless it had a cold weather efficiency greater than 4.85. At the time this necessitated a much more expensive heat pump which is probably where the 10k came from.

If we look at the Energy Saving Trust's current projections[0]. Someone with a relatively new boiler would expect to save £115/year. My energy provider offers a relatively cheap installation package starting at ~£3k[2]. It would take 26 years to pay off the air source heat pump at that rate. Their projections based on April's price data.

Many people require extra insulation and larger radiators to offset the reduced output temperatures of a heat pump. Radiators add an additional £200-300 each (£500+ if you're splurging) and a 4 bedroom family home will have a minimum of 6, more likely 8. If you end up spending £5000 overall it'd take 43 years to recoup the cost of changing your system.

On the bright side! If you're on an older boiler you could pay it off in under 10 years and if you're unfortunate enough to be on resistive electric heating, as far too many people still are, you'd break even in just over 3.

If we look back to March 2022 when energy prices were still inflated, Which[1] estimated that replacing your combi-boiler with a heat pump would cost you an extra £80/year. Should energy prices stabilise we'd expect to see the savings offered by a heat pump decrease. Which also estimates a much higher installation cost at £7,000-13,000. At the top end it'd take 113 years to pay for itself based on energy costs at what appears to be the peak of the gas crisis.

Ground source heat pumps are more efficient but the time to pay it off is similarly dire. The Energy Saving Trust estimates £24k to install one in a horizontal trench[3]. If you don't have the space or don't want bury a grid of pipework across your entire garden they estimate closer to £49k. They estimate a saving of £195/year. You'll break even in 123 years.

The issue with them is that they're a large capital investment that doesn't result in equally large cost savings. Until gas prices rise much closer to that of electricity, heat pumps will either cost more to run or will take longer than their expected lifespan to pay for themselves.

[0] https://energysavingtrust.org.uk/advice/air-source-heat-pump...

[1] https://www.which.co.uk/reviews/ground-and-air-source-heat-p...

[2] https://octopus.energy/get-a-heat-pump/#heat%20pump%20cost

[3] https://energysavingtrust.org.uk/advice/ground-source-heat-p...