On Sat, 26 Apr 2008 13:20:58 +0100, Rick Hughes wrote:
There are several of these about ... but of more interest would be:

1) heat pump ... remarkably more efficient, air-air easy enough but ground
to air, or water to air even better

Has anyone here managed to homebrew one of these? I did some reading up on
them a few weeks ago and the theory seems easy enough, but I'm not sure
how specialist some of the bits need to be...

(air-source isn't practical around here due to low winter temps, but
ground-source should be possible)