“Heat pumps are just air conditioners that go in both directions”
Statements like that probably paint an inaccurate picture of what modern monobloc enhanced vapor-injection (EVI) heat pumps with variable-speed compressors are capable of particularly in regard to efficient heating in cold climates.
Owners of such heat pumps, particularly ones which reduce or eliminate defrost cycles, frequently report desired temperatures being maintained in extreme cold temperatures with no additional heat.


