What to Do If Your Furnace Is Blowing Cold Air
Learn easy steps to troubleshoot and fix your furnace blowing cold air. From checking settings to inspecting parts, solve the issue quickly before contacting a professional.
There’s nothing worse than turning on your furnace on a chilly Colorado night—only to feel cold air coming from the vents. Before you panic, know that this problem can have a few simple causes, and in many cases, you can fix it yourself. At Flatirons Heating & Air, we’ve helped Greeley and Front Range homeowners troubleshoot furnace issues for years. Here’s what you should check if your furnace is blowing cold air.
1. Give It a Few Minutes
When your furnace first kicks on, it may blow cool air for a few minutes while it warms up. If it continues after 5–10 minutes, there may be another issue.
2. Check the Thermostat Settings
Make sure your thermostat is set to “HEAT” and the fan is set to “AUTO” instead of “ON.” When the fan is set to ON, it blows air continuously—even when the furnace isn’t heating—making it feel like cold air is coming through the vents.
3. Replace Your Air Filter
A clogged filter can restrict airflow, overheat your furnace, and trigger a safety shutoff. When that happens, the blower may still run, but no heat comes out. Changing the filter could solve the problem in minutes.
4. Inspect the Pilot Light or Ignition
For older furnaces, check to see if the pilot light has gone out. For newer models with electronic ignition, issues with the igniter can cause the burners not to fire, leaving only cold air blowing.
5. Look for Overheating or Safety Shutoffs
If your furnace overheats, safety switches shut off the burners, leaving just the blower running. This often happens from dirty filters, blocked vents, or mechanical issues that need professional attention.
When to Call a Professional
If your furnace keeps blowing cold air after you’ve checked the basics, it’s time to bring in a pro. Issues like failed igniters, gas valve problems, or faulty flame sensors require expert tools and training to diagnose safely.
Flatirons Heating & Air Can Help
If your furnace is blowing cold air, don’t wait until the next freeze. Our trusted team will get to the bottom of it quickly, repair the issue, and restore your comfort—so your family stays warm all winter.
Call/Text 970-534-9352 or schedule service online at flatironshvac.org.