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Why Is My Furnace Blowing Cold Air

It’s not much fun to expect warm air to blow from your registers only to get a blast of cold air. There are several things that can cause this, some of which you can fix yourself and others that need to be resolved by a professional.

Incorrect Thermostat Settings

Make sure the fan setting on your thermostat is set to AUTO and not ON. When it’s set to AUTO, the fan will only run when the furnace is on. When it’s set to ON, the fan will run constantly. This results in cold air blowing when the furnace is off. Also, check that it’s set to HEAT and not COOL.

Overheated Furnace

You’ll know your furnace is overheated if it blows warm air before blowing cool air, and then shuts off altogether. When your furnace overheats, the fan limit switch shuts off the burners. The most common reason for this is a dirty air filter. If the filter isn’t the problem, make sure all your supply vents are open.

Pilot Light Is Out

Older furnaces have a pilot light that’s always lit. A gust of wind can cause the pilot light to be extinguished. If you know what you’re doing, you can relight it yourself. Otherwise, you can hire a professional to do so for you.

Leaky Ducts

If you have leaky ducts, warm air can escape into unconditioned spaces before reaching the interior of your home. An HVAC company can inspect your ducts and fix any holes or gaps.

Broken Electronic Ignition

New furnaces have an electronic ignition. They can fail, which results in cold air blowing into your home. This problem needs the attention of an HVAC technician.

Certified Service of Burbank, CA, diagnoses and repairs furnaces when they’re blowing cold air or have developed other problems. We also replace and maintain them. We offer the same services for air conditioners and can help you with ductless AC mini-split systems. Please call Certified Service today to find out more.