Cugel wrote:from a couple of thousand to install highly configurable room-by-room controls of heating to tens or even hundreds of thousands for a windmill at the bottom of the (very long) garden. No subsidy on most, as the house had already had it via the previous owner when he first installed the ground-source tech and solar.
Room by room central heating is reasonably cheap, I fitted it myself using Honeywell gear. If you've got radiators and thermostatic valves it's a doddle since you simply swap the valve head (I didn't so had to do some actual plumbing).
Moderately cheap and good savings to be had.
With ground source heating and presumably underfloor heating you can do the same thing at the manifold although that's outside my experience other than knowing it's possible.
I looked at ground source heating but for me and as a retrofit I'll be dead by the time it starts to make a profit - either in monetary or carbon terms.
I also think that when my house gets sold it'll be demolished and several other houses built on the land making it overall less of a good thing.
OTOH in a few years gas boilers will be banned which presumably means that 'straight' gas boilers will be banned but hybrid 'air' heat exchanging boilers will be ok so I suspect my boiler (which is due for replacement) will end up being a heat exchanging boiler - just of the crappier variety.
As for solar, my roof will need replacing in a few years so I'm toying with hanging on and getting flush fit panels (they replace the tiles too so save a bit there). In the meantime I'm thinking I'll temporarily fit a couple to provide the tick over cost for the house. They're so cheap now I'm happy to forgo the FIT tariffs and do it myself.
Eventually when I get a proper system fitted (and a 'lecky car) I'll shift them elsewhere and plumb them in to other stuff.
Modern houses should be mandated to be fitted with solar (and possibly storage) along with solar water heating and grey water systems for loos etc.
This of course requires government intervention, as an optional extra builders would charge so much most folk wouldn't bother but as a mandated extra they'll simply absorb the costs because ultimately the price of houses is set by market conditions not what they actually cost.