Is a 2 stage heat pump more efficient in its first stage compared to operating in its second stage when operating in heat mode? It seems to me that the coefficient of performance would be a little higher in 1st stage but I have no data to back that up. Any thoughts?
And while we are on that subject, I have read in these forums that while operating in cooling mode 1st stage is more efficient. Is this because the smaller compressor/low speed still uses the entire condensing coil? And I am talking BTU/KW here, not perceived efficiency due to potentially increased dehumidification.