my system has been in since 1991: a closed loop geo thermal now probably buried in the bottom muck. It's workrd well,even with my cathedral ceilings and large windows facing southwest. My compressor is probably on it's last legs,too,although I think the buried pond loop is fine.the thermostat need to be set and left. My system is not a heat on demand,where you turn the thermostat down when you leave in the morning,then turn it up when you return.Back up heat is a 240volt heater that when on really turns the electric meter spinning! as far as seining,I,ll find out in about 7-8 years when I remove the paddelfish.
