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Why is My Furnace Blowing Cold Air?

The cold weather has rolled in and you’re looking to warm up the house, so you decided to turn your furnace on only to find that it’s blowing cold air. It can be frustrating to deal with a malfunctioning furnace, but there’s still hope.

If your furnace is blowing cold air, it could be multiple issues or one of many. However, many of these issues are ones that you can easily fix yourself. Before you call a professional for help, here is a list of troubleshooting tactics you can try:

1. Check the thermostat’s fan setting

Do you find that your furnace is only blowing cold air sometimes, but hot air other times? This could be an indication that your fan is set to “ON”. When it’s set to “ON” instead of “AUTO” your furnace fan will run 24/7 – regardless if the heat is on or not. In this case, simply change the switch to “AUTO” and the fan will only turn on when the furnace is heating the air.

2. Check the air filter. 

Your furnace may be blowing cold air because the filter is dirty. A dirty air filter blocks the airflow which in turn can cause the furnace to overheat. When this happens, a high limit switch will cause the furnace burners to shut off in order to avoid damage. If you find that your air filter is dirty, turn your thermostat off and simply change the filter and heating should resume to normal. Keep in mind that your system might have multiple filters. You will want to regularly check and change all of them.

3. Check that the Pilot light is lit.

When the pilot isn’t lit, the burners won’t ignite and your furnace will blow cold air. To relight the pilot, turn the thermostat off and follow the manufacturer’s instructions to relight the pilot. If you go through the steps of re-lighting the pilot, but it won’t stay lit, there’s likely a more serious problem at hand and you should call a professional for help.

If you are still experiencing issues with your furnace after checking these three things, it may be time to schedule a furnace check-up. It could be a more serious problem such as a malfunctioning circuit board, damaged ductwork, a faulty igniter, or a condensate blockage.

One of our certified HVAC specialists will come out to your home and inspect your entire system, locate the root of the issue, and provide you with multiple options to get your system up and running again.  

Contact us today! We can get your heat back on in no time.