[pharnorth]

We put a ground source heat pump system into our red brick 1950s farmhouse about 10 years ago. We had underfloor pipes run under all the floors (who led bloody cold winter with no heating while it was fitted) but it has been well worth it. The warmth is right across the house and you don't have the hot and cold spots you get with radiators.  150m coil runs under a paddock. It does trip off two or three times a year, probably be a use the start up current is high.....but then so do most systems it only takes a couple of minutes to restart. Replacing the old double glazing units and front door made a big difference last year but realistically you need to draft proof to get the best from any heating system. The cost savings are as others have given.

As a retro fit doing under floor is very disruptive but it is a huge benefit getting rid of radiators, it frees up a lot to of space. We reckoned a 12 year pay back when we did ours, but missed out on grants. When outside temp drops below freezing if we are lounging about we top up with an open fire.