Ask Absolute · Heating

What is emergency heat on a thermostat?

Direct answer

Emergency heat manually bypasses normal heat-pump operation and uses the backup heat source; it is generally for a heat-pump failure, not routine cold weather.

What this usually means

A functioning heat pump may automatically add auxiliary heat when needed. Selecting EM HEAT can increase energy use because the outdoor heat-pump section is taken out of normal operation.

Use the equipment and thermostat instructions, and arrange diagnosis when emergency heat is needed because the heat pump cannot operate.

What you can safely check

  • Confirm whether the display says AUX or EM HEAT
  • Check indoor temperature trend
  • Listen for outdoor-unit operation
  • Review thermostat instructions
When to call a professional

Call when emergency heat is required to maintain comfort or when the heat pump is iced, noisy or not operating.

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