Cloud nine eco houses use an ASHP and are only claiming a COP of 3 - 4.
GSHP claim a maximum of 6.
GSHP use the ground as the heat store, ASHP do not have a heat store/sink so I cant see how the ASHP can maintain COP 3 - 4.
If one has limited space, then solar PV and an ASHP would be a good combination, would be the most cost effective and be the most 'turn key' of any combination.
Of course, reduction in the form of less temperature difference and better insulation would be the first step.
food for thought.
Jon M
www.otherpower.co.uk
"I am certainly not a perfectionist, the thing is to know where you can take short c
