These are some other factors to consider when choosing and installing air-source heat pumps:

 

Select a heat pump with a demand-defrost control. This will minimize the defrost cycles, thereby reducing supplementary and heat pump energy use.

 

If you're adding a heat pump to an electric furnace, the heat pump coil should usually be placed on the cold (upstream) side of the furnace for greatest efficiency.

 

Fans and compressors make noise. Locate the outdoor unit away from windows and adjacent buildings, and select a heat pump with an outdoor sound rating of 7.6 bels or lower. You can also reduce this noise by mounting the unit on a noise-absorbing base.

 

The location of the outdoor unit may affect its efficiency. Outdoor units should be protected from high winds, which can cause defrosting problems. You can strategically place a bush or a fence upwind of the coils to block the unit from high winds.