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Is Your Furnace Blowing Cold Air?

Your furnace had a long summer vacation from heating duties, but now that winter is on its way, its blowing cold air! As frustrating as this may be, the answer may be a simple fix. If a  furnace blowing cold air has you stumped, here are some situations that might explain what’s going on:

  • Its normal – If you’re only getting a bit of cold air when your furnace first kicks on, but the air after a few minutes in is nice and warm, you’re likely just fine. Think of it like turning on a hot water tap. The same effect happens with your furnace. It must push out the cold air from the vents before the warm air can come.
  • Thermostat – If there’s a constant flow of cool air coming from your furnace, you probably have your thermostat set incorrectly. When you turn your furnace on for the first time, be sure that the fan is set to “auto” and not “on.” When your fan is set to “auto,” it will only come on when the furnace is on, instead of running all of the time.
  • Pilot light – If your furnace is only blowing cold air, your pilot light may be out. Double check your pilot light, and if it’s gone out, relight it. If you have to keep relighting your pilot light, contact a heating professional for an expert diagnosis.
  • Dirty sensors – If your furnace starts out warm but turns cold quickly, you could be dealing with a dirty flame sensor. A dirty flame sensor tells the furnace to turn off the burner, thus resulting in cold air after it’s initially warm. It’s best to call a heating professional to clean the sensor. Making sure to have annual furnace maintenance performed will help you avoid this issue in the future.

If a furnace blowing cold air is your issue, or if you need help with other home comfort issues, contact the professionals at HVAC Unlimited Heating & Air Conditioning. We proudly serve homeowners in and around Fairfax and Alexandria.

Get the value-focused & trustworthy service you deserve today!
  • For emergency service, please call our office at 703-493-1200.


We have staff on call 24/7 to provide assistance to our customers. We provide emergency service up to 8pm for all customers and 24/7 for contract customers. For quick, efficient emergency services, please call (703) 493-1200 immediately.