Furnace Blowing Cold Air : Causes and Fixes

Furnace Blowing Cold Air Causes and FixesIf your furnace isn’t producing hot air, then it’s time for some troubleshooting. Unfortunately, it happens to far too many homeowners. The time comes to turn on the furnace, but you are greeted with cold air. That’s not right! Well, chances are you are suffering from a common furnace problem. Here are the top causes and fixes for a furnace blowing cold air in your home!


First and foremost, let us explore the thermostat settings. By far the most common reason for a furnace blowing cold air is because the thermostat is set incorrectly. If your thermostat’s fan is set to ON, then the furnace will run day in and day out, even when the furnace isn’t producing hot air. As such, you’ll feel a gust of cold air from the ventilation.

Solution: Turn the thermostat fan setting to AUTO. Your furnace will now only blow hot air when needed instead of cold air all the time.


Another common issue with modern furnaces is overheating. If your furnace routinely blows out hot air, then cold air, then stops completely, chances are the system is overheating during use. The reason you receive a gust of hot followed by cold air is because of the limit switch. This switch is a safety device that shuts down the furnace burners when the system begins to overheat.

Solution: Chances are, the reason your system is overheating currently is because of a dirty furnace air filter. Your air filter should be swapped out monthly for the best results. Do not ignore an overheating furnace. If the system keeps this up, the heat exchanger may break down. Then you have a more expensive repair on your hands.

Pilot Light

Lastly, let’s take a look at the pilot light. If the furnace is only blowing cold air – no hot air whatsoever – then chances are the pilot light is out.

Solution: You can start by relighting the pilot light. If it remains on, then the problem is solved. Your other option, if the pilot light refuses to remain on after being relit, is to ensure gas is flowing into the furnace. The gas valve switch should be in the proper “on” position.

If you suspect trouble with your furnace, contact Metro Express Service at (817) 516-0700 for professional furnace repair!


Randy Murphy

Randy Murphy has been building his knowledge of the air conditioning and heating business for several years now. He first started applying his knowledge while working for his father’s HVAC company. Later, in 1987, Randy started his own business: Metro Express Service. He has been a top 10 Trane & Amana dealer for over eight years. When it comes to heating and cooling, Randy knows the business better than anyone.
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