What Causes a Furnace to Stop Working Overnight?

Most overnight furnace shutdowns come from thermostat settings, tripped safety limits, airflow blockages, or ignition problems. Typical causes include a dirty air filter, failed igniter/pilot, blower or electrical connector faults, gas supply or valve issues, and venting problems. Our technicians test all safeties, check for gas leaks, inspect the blower, burners, and heat exchanger, and run a complete heat cycle. Emergency troubleshooting is available 24/7 in Madison and nearby areas.

Quick checks:

• Set thermostat to Heat and raise the setpoint.
• Replace the air filter.
• Make sure the furnace area and vent are clear.

<br/> Updated: 2025-12-09 00:00:00 <br/> Need help in Madison, WI? Call (608) 255-6902 or book online.