Furnace Blowing Cold Air

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Why is my furnace blowing cold air?

The winter is upon us and there’s nothing worse than wanting to heat up your home but you’ve got a furnace blowing cold air instead of warm air. There are several reasons why this could happen. Here are the three most common reasons why your furnace can be blowing cold air.


The first step you should take if you are feeling cool air in your home is to check the thermostat. If you have the fan set to “ON” rather than “AUTO” this means that the fan will be running constantly. When the heater is not running the fan will blow cool air. If you set your thermostat fan to “AUTO” then it will only blow warm air when needed.

Another issue with your thermostat is that it could possibly be set to “COOL” rather than “HEAT”.  If that is the case, switch it to heat and wait a few minutes and it should start blowing warm air.


If your furnace is blowing hot air and then cold air and then it stops altogether you may be wondering what the problem is. Generally this could mean that it is overheated. There is a switch on the furnace called a limit switch. This switch was turned off which means that heat is not being produced yet the blower continues to run producing cool air. If your furnace has overheated it most likely means that you have a dirty air filter. Change your filters to see if your furnace blows warm air. If the problem is not solved by changing the filters, you should call in the professionals.

Pilot light

If you have a gas furnace and it is only blowing cold air then perhaps the pilot light is out. Relight the pilot light and hopefully this will do the trick. If not then you should seek a professional. For your own safety you shouldn’t mess with the gas lines in your home.

No one wants cold air blowing on them inside of their home when the cold air is whipping around outside. If you feel cool, check your furnace for these problems. If you are unable to fix the problem on your own, call in the professionals at Air Expo. We will get your furnace running properly to keep you and your family warm and cozy this winter.

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