Your furnace system is supposed to keep you warm while maintaining the indoor air quality in your house. But a furnace problem can affect even a relatively new furnace and result in the furnace is blowing cold air in your house. Here are 8 common reasons why furnace blows cold air.  

8 Common Reasons For Furnace blowing Cold Air

1. Thermostat issues

Several thermostat issues may result in blowing of cold air from your furnace. Choosing faulty settings is one. While ‘On’, ‘Auto’, and ‘Off’ settings are available, choosing the ‘On’ setting will just activate the fan, without producing heat.

Your thermostat could also be dirty from dust interfering with its ability to do its job right. An old thermostat could be another reason for this. If you’ve done a DIY job, you may not have installed the thermostat properly and this could end up blowing cold air from the furnace.  

2. Dirty air filter

The air filter of your furnace supplies the air for the burner to heat. Over time, this air filter gathers dirt, dust, debris and becomes dirty. This prevents air from passing to the burner system to get heated.

3. Issues with computerized controls

If you buy furnace, you may have a problem with computerized controls or the electronic control panel. You will need to reset the system by turning it off and then restarting it.  

4. Extinguished pilot light

An old furnace system functions with the pilot light being on. If this went off at any point of time, then your furnace will end up blowing cold air.  

5. Leaky air ducts

The air ducts of your furnace system are meant to carry  hot air throughout the rooms of your home. If there are any holes in the ductwork of your system, it could result in hot air escaping through the holes before being able to heat an area.    

6. Overheating furnace

If your furnace overheats, it will make the heat exchanger of the system very hot. The burner is then shut down with the fan limit switch detecting the excessive heat. The turning off of the burner results in cold air being blown throughout your house. 

7. Valve problems

A faulty valve will keep the pilot light turned off and result in cold air blowing from your furnace system. This could result from an unclean system or excess condensation.  

8. Faulty thermocouple

The thermocouple controls the ignition and valve. If there’s an issue with this, your furnace will blow cold air.  

Call a furnace repair professional if you face this issue and get it resolved easily to enjoy the warmth indoors.