Serving Chicagoland & Surrounding Areas


Why is my furnace blowing cold air?

digital temperature control

What makes our homes different from caves? If you said air quality and temperature, you are absolutely right. Nobody wants to come to a cold house that’s blowing cold air in the middle of the winter season. What are the potential reasons for cold air blowing out when you turn up the heat? 

 1: Dirty Flame Sensor

Annual maintenance is one of the best ways you can prolong your equipment life. Many furnaces don’t have pilot flames anymore and instead, they have safety devices such as flame sensors. If your flame sensor detector is covered in dust or insulated by lint (if your furnace is located next to the dryer), you will quickly lose heat and your furnace will blow cold air. That’s why cleaning that sensor is an important part of regular maintenance. 

 2: Air filter is Restricting Airflow

If you haven’t replaced your filter for some time, it becomes covered in dust and debris, which restricts the airflow to the unit. Blocked air or very poor airflow will cause overheating in your furnace, which will trigger safety devices and stop the normal function of your furnace.

 3: Low gas supply

If your furnace is blowing cold air, it may indicate that there is an issue with the gas supply to your house. Furnaces are designed to deactivate when they are not getting enough gas. This is not something that we recommend trying to fix on your own, and it’s better to call a professional as soon as possible to prevent any possible damage or safety hazards.

 4: There’s Damage To Your Ductwork    

You may get cold air when there are holes and cracks in your ductwork, depending on their size it can allow cold air to come in from attic space. Warmed air may be escaping from those cracks and the system is working harder, making your energy bills rise – nobody wants that.

 5: The thermostat is set to On instead of Auto.

The first thing you should do when cold air is blowing is to ensure the thermostat setting is correct, whenever “Fan” is set to ON position it will continuously have a blower fan running to circulate air inside your home. Even when your heat is turned off. 

If you are experiencing any of these problems, don’t hesitate! Contact the professionals at Duct Professor Inc. to handle all of your heating and cooling needs. For further questions, call us at (847) 744-8099