Take our house - bog standard turn of the 20th century terrace.
Garden / yard too small to install ground source pump for 3 bedroom house.
Installing an air source heat pump - upwards of £8,000.
This is no good without insulating the entire house and replacing all radiators with larger ones (reducing wall space available)
Internal wall insulation, at least £8,000
Removing or insulating chimney breasts - ??
Replacing suspended wooden floors with concrete and insulating them - ??
Insulating roof (rather than an attic floor, so that attic is still usable for storage) - ??
Replacing radiators - ??
Reinstating or replacing plumbing and electrics, bathroom and kitchen fittings, fitted kitchen - ??
Reinstating features - ??
Redecorating - ??
Cost of moving and storing furniture and belongings whilst insulation is installed - ??
Rental costs as house is likely to be impossible to live in - ??
I may have overlooked some things.
We would need tens of thousands of pounds. We don't have that kind of money. Any scheme based on receiving benefits wouldn't apply, we have two working adults, no children.