I don't disagree. But install costs are coming down. The RHI was available because it was still new industry in the UK and costs are higher in new industries. That actually reduces the total cost to me to £3.5 k not £7k. For that I got a house that is warmer and more comfortable. In my case also cheaper to run.
RHI is not available but both kit and equipment cost are now getting lower ( as the industry matures) and VAT has been removed on both kit and install costs so another saving.
Heat pumps have a 20 year life expectancy as well so over the long term it's actually cheaper. Also some are costs are one offs.
I do agree it was a big number but costs are going down not up. And as I said Octopus (and others) are committed to making install costs around the same as a boiler.
And a heat pump will be effective in a draft house with single windows. But it will be more expensive to run, as gas is.
Anyway, the UK has to move off gas to reduce carbon emissions. There are real issues with proposals for hydrogen (more expensive, untested, big adaptation needed, less efficient and so not reduce emissions as much). So at the moment choices are basically heat pump, district heating or other electric heating.
I haven't actually seen anything from Patrick Harvie saying it will be impossible to sell a house without a heat pump. Has anyone got a quote from him on that - not from Telegraph spin?