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Schedule NowPublished on January 30, 2026 by: alhhvac
Stay Warm All Winter with Andy Lewis / Hobson
There’s nothing more frustrating than cold air coming from your vents on a cold winter day. If your furnace is blowing cold air, it’s often a sign that something isn’t working as it should. Oftentimes, cold air coming from a furnace means higher energy bills, lower system reliability, and reduced comfort.
In this guide, the heating experts at Andy Lewis / Hobson Heating & Air explain the most common reasons a furnace blows cold air, potential at-home fixes, and how to know when to call a professional for fast, dependable repair.
Why Is My Heater Blowing Cold Air?
A heater blowing cold air can be due to a simple error or something more complicated. Here are a few of the most common culprits:
Thermostat or Fan Setting Issues
One of the easiest problems to overlook is the thermostat itself. If the fan is set to run continuously, your system may blow unheated air between heating cycles. This often leads homeowners to believe their furnace isn’t working when it actually is.
Restricted Airflow from a Dirty Filter
A clogged air filter can cause more than weak airflow. When airflow becomes restricted, the furnace may overheat and shut down the burners as a safety precaution. This leads to cool air circulating through your home.
Pilot Light or Ignition Failure
If your furnace relies on a pilot light or electronic ignition, any interruption can prevent heat production altogether. Without ignition, your HVAC system may still run, but it won’t deliver warm air.
Leaking or Poorly Sealed Ductwork
Damaged ductwork can allow cold air to enter the system before it reaches your living spaces. This is especially common in homes with ducts running through attics, basements, or crawl spaces.
Furnace Safety Shutdowns
Modern furnaces are designed to shut down when they detect unsafe operating conditions. When this happens, the blower may continue running even though heat production has stopped. This can make your home feel cold, especially during the winter months.
What You Can Check Before Calling for Repair
Before scheduling service, there are a few quick things you can look at:
- Make sure your thermostat is set to heat and the fan is on auto
- Replace the air filter if it looks dirty or clogged
- Confirm all supply vents are open and unobstructed
- Check for obvious duct disconnections
If none of these resolve the issue, it’s best to stop troubleshooting and call a professional. Continuing to run a furnace that’s malfunctioning can lead to expensive repairs and reduced indoor air quality.
When to Call a Local HVAC Company
If your furnace is still blowing cold air after basic checks, Andy Lewis / Hobson Heating & Air is ready to help. Our experienced technicians can:
- Pinpoint why your heater is blowing cold air
- Repair ignition and safety control issues
- Address airflow restrictions and duct leaks
- Restore reliable heat and system efficiency
With more than five decades of service in the Atlanta area, we know how to fix winter heating problems.
Get Reliable Heat This Winter with Andy Lewis / Hobson
Cold air coming from your vents is a sign your heating system needs attention. Andy Lewis / Hobson Heating & Air provides expert furnace repair and maintenance to keep your home warm, safe, and efficient all winter long.
Don’t wait! Contact us today for a free quote.
Frequently Asked Questions (FAQs)
Why is my furnace blowing cold air?
This usually happens due to airflow restrictions, thermostat settings, ignition problems, or safety shutdowns.
How do I fix a heater blowing cold air?
Start with thermostat settings and filter replacement. If the problem continues, professional repair is recommended.
Can HVAC blow cold air in winter?
Yes. HVAC systems can blow cold air in winter when heating components aren’t operating properly.
Why is my heater blowing cold air instead of heat?
Common causes include dirty filters, pilot light failure, duct leaks, or system overheating.
