It’s the “Worst Thing That Can Happen During the Winter”—a home furnace that suddenly stops heating. If it’s a cold day, this can be a serious emergency.
What to Do When Your Furnace Fails
When your furnace stops working, try these steps before calling a pro:
- Check whether the whole house still has power
- Confirm thermostat settings and that it’s powered on
- Inspect your circuit breaker panel for a tripped switch
- Make sure the gas line valve is open
For older furnaces, see if the pilot light is out
What do you do when you’ve got a cold furnace? The right answer is: “Call an HVAC professional to repair it.” But that’s only part of the right answer. There are some checks you can make first to see if the furnace stopped working for a simple reason. Once you’ve eliminated these basic mistakes and errors, you can reach out to a professional to come in and find out what caused the furnace to fail and then fix it.
See if the house still has power
When your furnace stops working abruptly during the day, it may be due to a house-wide or neighborhood-wide power failure. Sometimes you can miss the general loss of electricity if it’s still bright out. Check lights and appliances to see if this is the case.
(We should mention this now, otherwise it’ll come up over and over again: gas furnaces also must have electricity to run. Their blower fans run on electricity, and most modern furnaces use electronic ignition systems rather than standing pilot lights).
Check the thermostat settings
This may seem obvious—but that’s why people often overlook it. A simple incorrect setting on a thermostat can cause the furnace to shut off early or refuse to come on when it should. If you have a programmable thermostat, check to see if anyone has changed the program without notifying you. If you discover a blank thermostat screen, the furnace has probably tripped its limit switch and you should call for repairs. In some cases, a high-efficiency furnace may help reduce energy costs when operating correctly.
See if any circuit breakers have tripped
Open the electrical panel for the house and see if any breakers have tripped. We recommend having all the circuits labeled with the parts of the house they control so you can immediately tell which appliances are affected. If the breaker for the furnace has tripped, reset it and try the furnace again. If the furnace comes on, but the breaker trips a second time, there may be an electrical issue that’s worth repairing rather than replacing the system outright.
Check the gas line
The furnace has its own gas line with a valve on it so you can shut off gas flow in an emergency. See if the valve is closed or has become stuck.
Check the pilot light (if there is one)
Older furnaces that don’t use an electronic ignition system will have a pilot light. Examine the furnace cabinet to see if the pilot light has gone out. If you can’t relight it and keep it lit, and there isn’t anything wrong with the gas line, you should have a technician check the burners, as they may be the cause of the issue.
When it’s time to call for furnace repair in Davison, MI or the surrounding areas, you can trust us to make your home happy! (And that means you and your family will be happy as well!)
Frequently Asked Questions
Question: What should I do immediately when my furnace fails?
Answer: First, shut off the furnace at the furnace switch to stay safe. Then try a few basic checks like thermostat settings, power supply, and air filters. If those don’t resolve it, call a qualified HVAC technician.
Question: How can I keep warm while waiting for furnace repair?
Answer: Layer up with warm clothing, take a hot shower if your water heater works, use space heaters cautiously, cook meals to generate heat, and stay under thick covers.
Question: What troubleshooting steps should I try before calling a professional?
Answer: Check that the thermostat is set to “heat,” confirm power is on with the breaker and furnace switch, inspect and replace dirty air filters, and ensure vents aren’t blocked. If it’s a gas model, verify the pilot light or ignition system.
Question: When is it unsafe or inappropriate to attempt DIY fixes?
Answer: If you smell gas, if breakers repeatedly trip, or if issues involve the heat exchanger or electrical components, don’t risk it. Stop and call a licensed technician.
Question: Why is it helpful to report the symptoms to the technician when they arrive?
Answer: Sharing what you’ve tried and what you observed such as error codes, noises, or behavior helps the technician diagnose faster and come prepared with parts, which reduces repair time and cost.
Look to First Choice Heating & Cooling for furnace repair help. If your home had a voice … it would call First Choice!