What to Do When Your Furnace Goes Out

Furnace Troubleshooting Tips

Are you wondering how to identify possible issues with your furnace? We offer the following suggestions: 

Thermostat 

Make sure the thermostat setting is on “heat.” Seems like a no-brainer, but over one-fourth of furnace repair calls have been resolved by a professional simply moving the switch to “heat”. This can be an expensive service call for a simple issue you can check for yourself. Other things to check before making a furnace repair service call are: 

• Check the setting of the temperature.
• Set the temperature five degrees higher than what the temperature of the room temperature is currently to see if the heat turns on. 
• If you have a programmable thermostat, check that the display is correct with AM and PM settings and time.
• Check the wiring from the thermostat to the furnace. If there are any breaks or cracks, you can splice them back together or call for professional furnace repair service.
• Replace the batteries and then reset the thermostat.
• Gently blow any debris or dust out of the thermostat and make sure it is firmly on the wall and attached without any wiring sticking out. 
• If the program settings aren’t working,  bypass them by punching in the temperature you desire with the up/down control, then press and hold the button. This should switch the furnace on if the programming feature is broken. 

Breakers and Shutoff Switches 

This is another simple matter that has cost many homeowners a furnace repair service call that could have been taken care of by them. Check the on/off switch at the thermostat, on the furnace, and on the breaker box. If all of these things are on, an electric furnace is plugged in, and you are still not getting the furnace to work, then call for a professional furnace repair. 

The Filter

When was the last time you changed or cleaned the air filter? This should be done at least every 30 days, in some situations twice a month. When the air filter is clogged, the furnace will shut off because the airflow is restricted by the dirt and dust in the filter. 

The Gas

If you have a gas furnace that isn’t blowing hot air, make sure the gas valve is turned on. If the handle at the meter is perpendicular to the gas line, turn it to the parallel position. Check the pilot light, this is often an issue resolved during a furnace repair service that could be done by the homeowner.

Chimney Exhaust Flue

During cold weather, birds are attracted to the warmth of a chimney exhaust flue and will sometimes fall in, blocking the airflow. Turn the furnace off and the thermostat down. Then dismantle the duct and clear any birds, critters, or other debris that could be blocking. Reassemble and turn things back on. 

Drain Lines

If you have a high-efficiency furnace, it will drain several gallons of water every day during the winter. If the drain lines get clogged up and restricted from mold or sediment, the furnace will turn off automatically. Remove the hose and flush it with 25% bleach and 75% water for several minutes, then clear water for several minutes. Reattach and your furnace should start working again. 

Air Ducts

If there is still a room or two cold after the furnace comes on, you need to check if the air vents in each room are open. Next, check the air ducts in the attic. There may be a broken or crushed duct. A broken duct can be patched together with a metal duct tape. A crushed duct will need to be replaced. 

Clean Debris and Leaves 

If your furnace vents are outside, check that the vents are clear of any debris and leaves. If you aren’t finding anything blocking the vent, you’ll need to make that furnace repair service call. 

How do you keep warm when your furnace goes out?

If you wake up one morning, or worse, in the middle of the night, and the house is cold, you should check the furnace first thing. Follow the steps we listed above to see if you can get it working before making that furnace repair service call. And in the meantime, to keep warm until the technician arrives, here are a few suggestions: 

1. Use space heaters 
2. Use the fireplace
3. Keep doors and windows closed
4. Keep blinds, curtains, and shades closed
5. Dress warm and keep moving 
6. Turn on the oven and cook a pot of chili or stew
7. Make pallets in the floor and have slumber party

How do you reset a furnace?

Every furnace should have a reset button; this is an important feature with HVAC systems for safety purposes. They will shut the furnace off if there is any malfunction of the furnace. You can reset a furnace with these steps: 

Reset an Electric Furnace

1. Turn the power to the furnace off at the breaker.
2. Press the reset button. Usually this is located inside the blower compartment at the side of the blower motor.  
3. If the button pops back up after you press it down, call your furnace repair service company.
4. If the button stays down, the furnace should cut on and you can replace the cover to the blower compartment.

Reset a Gas Furnace

1. Check that the pilot light is on.  
2. Turn down the thermostat setting to the low setting.
3. Turn off the power supply at the breaker.
4. Turn off the main gas supply off at the furnace but  leave the pilot gas supply on.
5. Relight the pilot light.
6. Turn the circuit breaker on, and then turn the main gas supply on.
7. Press and hold the reset button for thirty seconds and raise the thermostat to the correct setting. 

What is the average cost of a furnace repair?

You should have your furnace checked prior to winter using a furnace repair service near you. By doing this, you establish a relationship with a trusted source, and you won’t need to worry about who to call for furnace repair in an emergency. This check-up and tune-up can cost around $150 unless there are parts or a furnace repair needed at the time. 

The average cost for a furnace repair can start around $150 and go as high as $500, depending on the type of furnace, electric or gas, and the age/model of the furnace. Gas furnace repairs usually cost more because they are more complex than the average electric HVAC furnace.