Heat Strip / Auxiliary Heat

What auxiliary heat does in a heat pump system

A heat pump heats by moving heat from outdoor air into the house, and its capacity falls as outdoor temperatures drop. Heat strips are the safety net: coils of electric resistance wire, rated in kilowatts, mounted inside the air handler. The thermostat energizes them, often in stages, when the heat pump cannot satisfy the call on its own, when indoor temperature falls well below setpoint, or during defrost cycles so the system does not blow cold air. Most thermostats show an indicator such as 'aux heat' or 'emergency heat' when the strips are running.

Resistance heat works, but it is the most expensive way to make warmth, since it converts electricity directly to heat instead of moving heat the way the compressor does.

Managing auxiliary heat during Pennsylvania winters

In a Southeastern Pennsylvania winter, occasional auxiliary heat on the coldest nights is normal. Strips that run constantly are not. Frequent aux operation can point to a low refrigerant charge, an undersized or aging heat pump, a thermostat programmed with large setbacks that force recovery on strip heat, or an outdoor unit that is icing up. If your electric bill jumps in winter or the aux indicator rarely turns off, have the system diagnosed; PJ MAC HVAC repairs heat pumps along with gas and oil heating equipment.