Why Is My Furnace Blowing Out Cold Air?
3 minutes read

Why is my furnace blowing out cold air?

Published by Steven Weiland

Is your furnace blowing out cold air? This is obviously the opposite effect than you’d like, especially when it is cold out. There could be a number of reasons why your furnace might be blowing out cold air. This could be a major problem with your furnace and it could require a repair, but chances are it is something you can fix yourself. One of the following may be the issue:

Furnace hasn’t been on long enough

If you are noticing cold air immediately when you turn your furnace on, this is not an issue. The furnace needs to blow the cold air out of your vents before it can start circulating warm air into the home. Wait a few minutes for the furnace to get going. Once it is all booted up, then judge the temperature of the air. Hopefully it starts to get warm. If not, you may be dealing with one of the subsequent issues.

Thermostat fan setting is on

Check to see that your thermostat’s fan setting is set to “auto” rather than “on”. If the fan is on, the blower will run even when the furnace isn’t heating the air. If the fan is set to auto, then it will only blow warm air.

Dirty air filters

One thing that might be wrong is that your furnace’s air filters are dirty. When air filters become too dirty, they block air flow. This means that the furnace has to work harder to heat your home, and when this happens, the furnace may overheat. Overheating causes the furnaces’ burners to turn off as a safety precaution. The fan will keep blowing to cool the furnace down. Make sure to frequently change air filters to eliminate the likelihood that this will happen. If your furnace overheats too often, you could have an expensive problem on your hands.

Extinguished pilot light

Gas furnaces have a pilot light that should always be burning. Sometimes, for whatever reason, this light goes out. It is there to This could be the reason that your furnace is blowing out cold air because it is not igniting the burners. You can go in manually and relight this pilot light. If it won’t light, it could mean that your furnace is not receiving an adequate supply of gas.

Flame sensor needs to be cleaned

Another issue that may arise is that the flame sensor in your furnace is dirty. If dirty, the flame sensor will read temperatures inaccurately and make adjustments to how the furnace is operating accordingly.

Something more complicated

If you cannot identify any of the above problems, there may be a larger problem at stake. Something more complicated may be the issue. If that’s the case, it’s time to call an HVAC specialist. Additionally, if you are not, yourself, confident in fixing any of them, then it may be time to call an HVAC specialist. If you find yourself asking “Why is my furnace blowing out cold air?” then give Heatmasters a call.

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