Why Is My Furnace Blowing Cold Air?
Turning on your furnace only to feel cold air from the vents can be frustrating—especially during chilly weather. At Integrity Air Solutions, we often hear this concern, and fortunately, there are several common reasons behind it. Here’s what might be happening and how to address it.
Common Reasons Your Furnace Is Blowing Cold Air
Thermostat Issues:
Check your thermostat settings first. If it’s set to “ON” instead of “AUTO,” the fan may run constantly—even when the furnace isn’t heating. Set it to “AUTO” to ensure warm air only blows when the system is heating.
Dirty Air Filter:
A clogged air filter can restrict airflow and cause the furnace to overheat. When this happens, a safety switch may shut off the burners, leaving only the fan running and pushing out cold air. Replace the filter to restore proper airflow.
Pilot Light or Ignition Problems:
If your furnace has a standing pilot light and it’s out, the burners won’t ignite. For newer models with electronic ignition, faulty components may also prevent the furnace from producing heat.
Overheating Furnace:
When a furnace overheats, it will shut off its burners as a safety precaution. This can happen due to blocked vents, dirty filters, or internal mechanical issues. Once cooled, the blower may continue to run, but only cold air will come out.
Leaky Ducts:
Air ducts with holes or gaps can let warm air escape and pull in cold air from unconditioned spaces, making it feel like the furnace is blowing cold air even though it’s heating.
Conclusion
