Re: At 7F outside heat pump maintained 73F indoors
Did you do the Manual J on the house yourself or did the HVAC guys do that as part of building up the proposal?
Just out of curiosity, what were your design conditions and the resulting heat loss and gain? Did they estimate a balance point? You must have a huge load to support 2x 48,000 BTUH systems.
I am also surprised that with the unit only putting out 25 MBh @7*F it was able to hold the house. Your balance point must be very low. -- The difference between genius and stupidity is that genius has its limits.