AUX heat Archives - Advanced Heating & Air Conditioning

Heat pump thermostat showing AUX HEAT during cold weather in a Temecula Valley home

AUX HEAT keeps popping up on your thermostat? It's normal backup heat helping the heat pump under certain conditions — but constant, unexplained AUX can spike your bill. Here's w

Heat pump thermostat displaying AUX HEAT in a Temecula Valley home during winter heating

October 6, 2026

Heat PumpsHeatingHomeowner Guides

by Advanced Heating

Auxiliary Heat vs. Emergency Heat on a Heat Pump

Saw AUX HEAT or EM HEAT on your thermostat? They're related but not the same. Here's what auxiliary and emergency heat each do, when they're normal, why they can spike your electri

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