Ladia,
You mean you have one meter for HVAC and another for the rest of the house?
When you said above "using geo for heating only" you lost me. My system is a forced-air heating and cooling system, just like most conventional heat pumps. This is it's only function, the domestic hot water is just icing on the cake.
I know they make geo units that only do one thing...heat water. Some people use them to heat swimming pools and radiant floor systems. Is this what you were referring to?
Is your radiant floor in concrete or under a wood floor?
Yes we have two meters. The utility charges the wholesale rate just in the heating season.
There are three basic Heat pump arrangements: Heating only, cooling only and reversible heating/cooling. To achieve maximum efficiency it is important to use the heat pump optimized for your particular climate and type of the heating system such as floor, hydronic (with radiators) or forced air.
We have floor heating with PEX embedded in concrete slab. Since the efficiency of the heat pump is inversely dependent on the temperature differential the floor heating is probably the most efficient because it has the smallest temperature differential.
Needless to stress the obvious: The best heating is insulation, insulation and insulation.
