PeterL wrote:
Does anyone have any views or experience, please? Good or bad.


Views and research yes, experience no.

Because the costings indicated it wasn't worth it yet. In my case.

Some things I learnt. (ground source only)

1/. For a decent output, you need a pretty big garden. Ok here.

2/. For a decent output, you need a pretty big pump. Enough to strain a
single phase..three phase better.

3/. Its best delivering a lot of warm water: efficiency is poor at
delivering hot water.

4/. Because of that, you need a lot of radiator or UFH.

5/. Because of that you need rather larger pipes in your CH circuits.

6/. Because of that you need rather more coil in the tank heat exchanger
for hot water.

7/. Because of that you need a supplementary imersion heater to get teh
water up to say 55 or 60C to make it sterile and safe in hot wate circuits,.

Bceause of 4,5 and 6, I was facing a complete replumb: hat pushed teh
cost upp to about £20k.

IF I had been green fielding, I would actually have done it though. It
should be fuel cost competitive with oil at 30p a liter.


However, with oil costs at £2500 a year these days, I might save £1000 a
year BUT the installation looked like about 20 grand with all the mods.

I may live beyond 20 years, but probably not here..