It’s a frustrating experience to turn on your furnace only to have it blast cold air – especially when it’s dipping to 30 degrees or below at night. You’ve checked to make sure the temperature is set where you want it, but still, all you feel is cold, uncomfortable air. So what does it mean if your furnace is blowing cold air? Here are a few common causes we come across during our repair visits.
1. The Fan is On
You should first check to make sure your fan is set to “auto” and not just “on.” Why? Sure, you want the fan to turn on when the heater is running – but not when it isn’t. When set to auto, your fan will turn itself off unless the heater is actively working. This ensures that you’re only getting warm air blowing from your air vents, and that your feet stay toasty and warm.
2. The Pilot Light is Out
For your gas furnace, you’ll need to check the pilot light. If the pilot light is out, then your furnace will definitely be blowing cold air. If you’ve never lit the pilot light before, check your owner’s manual, YouTube videos, and other online materials. But remember, if you don’t feel comfortable lighting the pilot yourself, call your local utilities company and they’ll come out and relight it (and show you how to do it in the future). Better safe than risking a deadly gas leak in your home!
3. The Air Filter is Dirty
A dirty air filter is a BIG problem that in itself will lead to other issues. Namely, a dirty air filter can cause the heater itself to get too hot and overheat, which will result in the issue of your furnace blowing cold air instead of hot air. Make sure to check and change your air filter regularly.
4. The Ducts are Leaking
Leaky or damaged air ducts will greatly reduce the efficiency of your furnace. The escaping air will cool off, giving the impression that your heater isn’t working or warming up the air as it should be. Schedule regular duct cleaning inspections with your HVAC specialist.
5. The Flame Sensor is Broken
If your flame sensor is dirty or broken, it will prevent the gas burner from staying lit for as long as it needs to in order to bring your home to temperature. Call your HVAC technician to inspect the flame sensor and identify the cause of your cold air issue.
What does it mean if your furnace is blowing cold air? It means that your furnace needs attention, and that you don’t have to be living in misery all winter long! If you cannot identify and remedy the problem yourself, call your heating specialist to get your furnace back on track.