Furnaces
What to Do If Your Furnace Stops Working
By Tom Moor•December 9, 2024
Imagine it’s the middle of winter and it’s freezing cold outside, but you’re warm and comfortable under a blanket, enjoying the view of falling snow through the window. That’s when things take a turn for the worse. You notice it’s getting colder inside, and the temperature has dropped below what’s set on your thermostat. You then realize the furnace has stopped working. Yikes!
It’s easy to panic in this situation, but staying calm and troubleshooting the issue can help restore heat to your home or at least make it easier to explain the problem to an HVAC technician. Here’s what you can do if your furnace stops working to keep your home warm and safe.
Troubleshooting a Furnace That Won’t Start
1. Check the Thermostat
The first thing to do is check the thermostat. It’s possible someone accidentally set it too low or switched it from heating to cooling mode. If the screen is blank, replace the batteries.
2. Inspect the Furnace Filter
If the thermostat is fine, next check the air filter. A clogged filter restricts airflow, which can cause the furnace to shut down to prevent overheating. It can also reduce airflow from the vents, making it seem like the furnace isn’t working properly.
3. Ensure the Furnace Is On
Look for the disconnect switch near the furnace – it’s similar to a light switch and turns the furnace off without needing to access the electrical panel. If it was accidentally switched off, simply flip it back to the “on” position.
4. Check the Circuit Breaker
Your furnace has its own dedicated circuit breaker. Check your breaker panel to see if it’s tripped, and reset it if necessary. Also, inspect for a blown fuse and replace it if needed. If the fuse blows again or the breaker continues to trip, it’s time to call a professional.
5. Check the Pilot Light
If you have an older furnace, check the pilot light. It may have gone out due to a draft, a dirty thermocouple, or a gas issue. To relight it, turn the gas valve off, wait a few minutes, then follow the manufacturer’s instructions to safely relight it. If it won’t stay lit, contact a technician for help.
6. Call an HVAC Professional
If none of the above steps restore heat, it’s time to call a technician. You could be dealing with a more complex issue, such as a faulty blower motor, a cracked heat exchanger, or problems with the gas line.
Tips to Stay Warm When the Furnace Stops Working
Unfortunately, during extremely cold weather, HVAC technicians may be backed up due to high demand. It could take several hours or even a day or more to get service. Call a technician early to schedule an appointment. In the meantime, here are a few ways to stay warm:
- Close off unused rooms to keep heat concentrated in the areas you’re using.
- Layer up with warm clothing, blankets, or even sleeping bags.
- Use space heaters safely in key rooms, making sure to turn them off when leaving a room.
- Cook on the stove to generate heat, but never leave it unattended.
- Cover windows with curtains or blankets to minimize heat loss.
How to Prevent a Furnace Breakdown
The best way to avoid a furnace breakdown during winter is through regular maintenance. Schedule a furnace tune-up before the heating season starts. A technician will inspect and clean key components like the burners, heat exchanger, and blower, check for safety issues, and ensure the system runs efficiently.
Also, remember to change your air filter every 1-3 months, depending on system usage and factors like having pets.