No Heat from Vents
Quick Answer
When no heat comes from your vents, first check that your thermostat is set to HEAT mode and the temperature is set higher than the current room temperature. Then check your circuit breaker. These two simple checks solve about 50% of no-heat calls.
Safe Checks You Can Do
- 1Check thermostat - Confirm HEAT mode, temperature above current, and batteries are fresh.
- 2Check circuit breaker - Look for tripped breakers. Furnaces may have two breakers.
- 3Check furnace switch - There's usually a light switch on or near the furnace. Make sure it's ON.
- 4Replace air filter - A clogged filter can trigger safety shutdowns.
Likely Causes
- Thermostat issue
Wrong setting, dead batteries, or faulty thermostat can prevent the furnace from activating.
- Tripped circuit breaker
Power surge or overload may have tripped the furnace breaker.
- Pilot light out
For standing pilot furnaces, the pilot may need to be relit.
- Gas supply issue
Gas valve closed, gas line issue, or gas company interruption.
- Ignition failure
Electronic ignition systems can fail, preventing the burners from lighting.
When to Call a Pro
- You smell gas
- Thermostat and breaker checks don't help
- Furnace makes clicking sounds but won't ignite
- You see error codes on the furnace display
- It's below freezing and you have no backup heat
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