I have an Carrier air heat pump at the back of my house (installed 1 year ago). It is generally fine and stays defrosted with the smaller amounts of ice/snow. With a larger amount of snow, should I consider building a temporary lean-to above it to keep snow away from the unit? If so, how high above the unit should it be to not impede air flow?
There are several advantages to having a permanent roof over an outdoor heat pump:
- keeps direct sunlight off during cooling season
- keeps rain, leaves, twigs, and branches further away and keeps the unit cleaner
- no freezing rain can put the blower out of balance with lopsided icing
- keeps snow away from the top and sides where it would impede airflow
- possibly provide some noise reduction
The first installation manual I could find says (page 7) there should be a 48 inch (120 cm) minimum space above the unit.
Depending on the typical maximum snow accumulation, I would extend the roof out at least three feet from the edges of the unit. This also avoids the problem of the roof supports from blocking service access (some units have hinged panel doors).