Why is My Furnace Blowing Cold Air?

The peak of winter is not when you want to deal with furnace problems. You depend on this vital appliance to keep your family warm and comfortable.


However, as with any appliance, sooner or later your heating system may stop working properly. But instead of a broken coffee maker, leaky dishwasher, or faulty ice maker, it’s a necessity to have your furnace working well when temperatures are frigid!


First things first – check your thermostat settings


If you have felt cold air blowing out of the vents in your home, check your thermostat. Many people will set their fan to “on” instead of “auto” as they believe this will help to keep warm air circulating throughout all areas of the home.


However, a fan set to “on” will result in air constantly being blown through your vents, even when the furnace isn’t running. This may be why you have noticed that cold or room-temperature air is flowing through your ductwork.


When was the last time you replaced your air filter?


If you can’t remember, then now is the time to swap it out with a fresh one. Clogged filters make it nearly impossible for warm air to travel from your furnace and through the ductwork to the vents of your home.


In addition to restricting air flow, a severely clogged filter may cause the burners of your furnace to shut off. There is a safety mechanism in your heating system that is designed to protect the unit from overheating when air flow has been compromised. Not only this, but a dirty filter means your family is breathing polluted air!


Issues with your furnace’s ignition system


If your filter was recently replaced, and your fan isn’t set to “on,” the problem with your furnace blowing cold air could be a result of a malfunctioning igniter or pilot light. If your heating system isn’t receiving a spark to “light” its fuel, warm air won’t be generated.


Problems with your ductwork


Your heating system may be working just fine, but if your ducts are clogged or leaky, warm air won’t make its way into your living space. If you haven’t had your ducts inspected recently and this is the problem you’re experiencing in your home, it may be advantageous for you to have them looked at.


The condensate line is clogged


You may have heard of this component on an air conditioner, but many modern high-efficiency heating systems make use of this mechanism to remove excess water created during the heating process. When the drain line gets obstructed with dirt and dust, a safety feature of the furnace will prevent the burners from functioning like normal, leaving you with a chilly home.

Other common furnace problems you may be experiencing:

  • Furnace is leaking
  • Unit is randomly switching on/off by itself
  • Heater won’t come on at all
  • Furnace only seems to be heating rooms closest to where it’s installed

Let a professional diagnose the problem


While you may consider yourself an expert do-it-yourselfer, heating repair work is best left to the trained professionals.


If you are enrolled in one of our heating repair plans and notice any of the above-mentioned problems, give us a call or fill out our online form to schedule an appointment with a local heating expert.