When your furnace starts blowing cold air instead of warming your home, it can be frustrating and uncomfortable—especially during the winter months. While this problem may seem serious, it could be for a simple reason that can be resolved quickly, or it could be a sign of a more significant issue that requires professional furnace repair in McMurray. Below, we’ll go over five possible causes.
1. Thermostat Issues
Before assuming something is wrong with your furnace, check your thermostat settings. A thermostat set to “ON” instead of “AUTO” can cause your furnace fan to run constantly—even when the system isn’t actively heating the air. This can result in cold or lukewarm air blowing through your vents.
If your thermostat’s batteries are low or its wiring is faulty, it may fail to communicate with the furnace properly. Smart thermostats can also experience connectivity issues, leading to inaccurate temperature readings or failure to trigger the heating cycle.
2. Overheating and Safety Shutoff
Modern furnaces are designed with built-in safety mechanisms to prevent overheating. If your system gets too hot, it will shut down the burner while still running the fan, which can result in cold air being pushed through the vents.
Overheating can be caused by restricted airflow, often due to a clogged air filter, which causes the furnace to work harder and potentially overheat. Closed or blocked vents can also contribute to overheating by disrupting the flow of warm air.
If your furnace is repeatedly overheating and shutting down, it may be a sign of a more serious mechanical issue that requires professional service.
3. Pilot Light or Ignition Problems
For gas furnaces, the pilot light or ignition system is responsible for lighting the burners that generate heat. If the pilot light goes out or the electronic ignition system malfunctions, the furnace won’t be able to produce warm air. Older furnaces with standing pilot lights and newer systems that use electronic ignition can fail due to electrical problems or wear and tear over time. If your furnace repeatedly fails to ignite, have it inspected by our team.
4. Dirty or Faulty Flame Sensor
The flame sensor is a small safety device that detects whether the burners are lit. If it doesn’t detect a flame, it will shut off the gas supply to prevent unburned fuel from accumulating—a crucial safety feature.
Over time, the flame sensor can become covered in soot or residue, preventing it from accurately detecting the burner flame. Regular furnace maintenance by our team can prevent this issue.
5. Ductwork Leaks or Blockages
Even if your furnace is working properly, leaky or blocked ductwork can cause warm air to escape before it reaches your vents. Blockages in the ducts—caused by debris, dust buildup, or even pests—can also restrict airflow, preventing heated air from reaching your living spaces. If you notice uneven heating, higher energy bills, or excessive dust in your home, your ductwork could be the culprit.
If your furnace is blowing cold air, don’t panic—many common causes have simple solutions. Start by checking your thermostat settings, air filter, and pilot light to rule out basic issues. However, if the problem persists, it’s best to contact us.
Call the friendly staff at Boehmer Heating & Cooling for exceptional customer service! Schedule furnace repair in McMurray, PA with our team today.