SEER Calculation

The Seasonal Energy Efficiency Ratio is calculated for all year performance using 'standard conditions for each month of the 'annual' period. A heat pump will have a very high 'EER' of Coefficient of Performance (COP) during mild heating conditions --as much as 3 times that of electric resistance heating

There are two different measures that are important--what is the EER during the cooling season, an what is the EER during the heating season, and how much of each season do you experience where the unit is located.

As example, 650 watts of electrical resistance heating will generate about 2200 BTU/hr of heat (EER= 3.1, COP=1.0). However, if that 650 watts is used to 'pump' heat up a few degrees- say from 50F to 70F), then some 20,000 BTU/hr can be transfered from 50F outside air to 70 F inside air (EER = 30.9, COP = 7.3).

The heat pumps I've been looking at recently typically have low SEERs, so that figure does not look out of line.

If you were contemplating using a heat pump with a static pressure of 0.3"wc, would you add the return duct loss to the supply duct loss to determine the adequacy of the unit?