I was looking at some of the houses for sale in eastern Pennsylvania.

Since there is massive building going on in SEMI-RURAL areas for all the NJ and
NY people currently moving there, I notice that some of the houses both new and
old have HEAT PUMPS for their source of heat.

I have always heard that heat pumps are NOT that effective in COLD climates.
The weather in this area can get to the 20º and below mark for long stretches.
In a BAD year, the temps can linger at 10º for long periods of time.

Comments ?
TIA