What Are Common Reasons My Heater Is Not Working in My House?

The most common reasons a home heater won’t run are thermostat or power issues, airflow restrictions, and ignition or sensor faults. In Portland and Clackamas, we often find dirty filters, tripped breakers, clogged condensate drains, failed flame sensors or igniters on furnaces, and low refrigerant or iced outdoor units on heat pumps.

Quick checks:

• Set thermostat to Heat and replace batteries.
• Check the breaker and furnace switch.
• Replace a dirty filter and clear vents/returns.
• For heat pumps, clear debris from the outdoor unit.

Updated: 2025-12-10

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