Furnace Not Heating

Furnace not producing heat? Learn common causes, DIY troubleshooting, and HVAC repair costs ($150–$500).

Typical repair cost: $150–$500 · DIY difficulty: Easy · About 15–30 minutes.

What usually causes it

• Dirty air filter
• Thermostat malfunction
• Pilot light out (older furnaces)
• Ignition failure
• Gas supply issue

What you need

• Replacement air filter
• Flashlight

How to fix it yourself

1. Check thermostat — set to 'Heat' and above current room temperature
2. Replace the air filter if clogged
3. Check if the furnace is receiving power (check breaker)
4. For older furnaces, check if the pilot light is on
5. Ensure gas valve is in the 'on' position
6. If furnace starts then shuts off quickly, it may need professional service

When to call a pro

If you smell gas, the furnace repeatedly cycles on and off, or it won't ignite after checking the basics.

Get a fixed price from a local pro