Vent, Valve & Volt
Heat pump not heating, or blowing cool air

You can fix this

Likely cause: a thermostat setting

If the thermostat is on Cool or the fan is set to On, you'll feel cool air. Set it to Heat with the fan on Auto.

Why this happens

Trane and Carrier both list the thermostat setting first for a heat pump that isn't heating. With the fan on On, the blower runs between heating cycles and moves air that hasn't been heated. Carrier also lists an uncalibrated thermostat further down its list.

How to fix it

  1. Set the mode to Heat, not Cool or Emergency Heat, and the fan to Auto.
  2. Set the temperature a few degrees above the current room temperature.
  3. If the thermostat runs on batteries and the screen is dim, replace them.
  4. Wait several minutes, then feel the air at a vent.

If this does not fix it, tell the HVAC technician

  • What the thermostat was set to.
  • Whether the air warmed up after you changed it.
  • The thermostat brand and model.

Build the full list: what to tell the HVAC technician.

Start this troubleshooter over

References (every fact above comes from one of these pages)
  1. Trane: Heat pump not heating
  2. Carrier: Heat pump not heating

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