By Greg, Pacific Aire Comfort Advisor,
Heat pump efficiency usually exceeds conventional A/C and heating, particularly here in Southern California where winters are mild. An air-source heat pump can generate up to four times more energy in the form of heating than the amount of energy it consumes.
Without attention to airflow, ducts and proper refrigerant charge, however, much of those efficiency gains can be negated. Here are five important tips to make sure you get the heat pump efficiency you’re paying for:
- Heat pumps function most efficiently at higher cubic feet per minute (CFM) of airflow than a conventional A/C and furnace. Your duct system should be sized to accommodate 400 to 500 CFM of airflow per ton of heat pump capacity for optimum performance.
- To sustain adequate airflow, under ideal conditions every room with a supply register should have at least one return register. Rooms lacking a return register must have a clear air path to a shared return via a grille in a doorway or a jumper duct running through the ceiling.
- Most ductwork that was part of original construction is probably leaking. Make sure your HVAC contractor pressure-tests the ducts, and ask that the ducts be sealed so leakage is less than 10 percent of total system airflow. If ducts are routed through unconditioned zones of the home like the attic or crawl space, they should be insulated to a value of R-8.
- Make sure wall cavities or the channels between ceiling joists are not utilized as substitutes for proper metal ductwork — a frequent cost-cutting method of decades past.
- The refrigerant charge in residential split-system heat pumps is added during installation. The amount of refrigerant should be checked by the technician per manufacturer’s specs for pressure and temperature at start-up and again after the unit has been test run. A heat pump with low refrigerant levels will not deliver the efficiency ratings promised by the manufacturer.
Pacific Aire Heating & Cooling has been solving indoor comfort issues for homeowners in Ventura, northern Santa Barbara and western LA County areas including the San Fernando, Santa Clarita and Conejo valleys since 1990. Give us a call and let us show you the way to higher heat pump efficiency and performance.
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