My home has a geothermal heatpump that is about 2.5 years old. The heat pump cannot keep up when it gets too hot out. I live in Tennessee, and the temperature was in the high 80s and low 90s for significant portions of this past summer. During those times, my whole house heats up to around 6-8 degrees higher than I've got the thermostat set, and the heat pump runs constantly. Needless to say, this jacks up my power bills, and that kind of defeats the purpose of having the geothermal heatpump in the first place.
I've talked with the contractor that installed the heat pump, and they insist that it is the right size for my house. But they say that it just won't be able to keep up when it gets that hot. honestly, this seems like BS to me, it seems to me that either the heat pump can keep up, or it is undersized.
Anyway, I wonder if anybody has suggestions for how to improve the situation. Is there any kind of supplemental system that can be used with a geothermal heat pump, something along the lines of the aux heat coils that standard heat pumps use when it gets too cold?