Hansberger Refrigeration Blog: Your AC Repair Resource

Why Would Your Furnace Be Blowing Cold Air Into Your Home?

Worried woman calling a boiler breakdown service at home, her boiler is not working

You turn your furnace on. The air is blowing, but it’s still not warm. What could be wrong? Here are a few reasons why your furnace might be blowing cold air and what to do to fix the issue.

  • Thermostat setting. The first thing to check is your thermostat’s fan setting, as it may be a simple fix to keep the unit from blowing cold air. If your fan is set to “On,” it will blow air continuously, even when the furnace isn’t running. By switching it to “Auto,” you save energy and ensure warm air whenever your furnace runs.
  • Pilot light. If your furnace is older, check the pilot light, which is the little flame that feeds the heat that warms your home’s air. If the flame goes out, the furnace will blow cold air. If you still have a manual model, follow the instructions for how to relight it. However, consider investing in a newer model that doesn’t rely on a pilot light. Not only are they more convenient, they’re safer and use less energy.
  • Flame sensor. In more modern furnaces, the flame sensor regulates gas flow by detecting heat. It will shut off the gas valve if it doesn’t detect a flame to burn that gas, thus preventing gas leaks. However, if the sensor is broken, it may fail to detect the flame even when it is there and shut off the gas accordingly, preventing the air from being heated. Smart thermostats will often alert you if this happens, though you can also check the sensor itself to see if it’s cracked or damaged. If it is, call your HVAC technician to repair it.
  • Gas supply. There may be a problem with the gas line that supplies the flow of natural gas to your home. Without gas, there’s no fuel for your furnace to provide heat and it will just blow cold air. If you suspect there’s a problem with your home’s gas supply, call the gas company out to take a look.

To make sure your furnace blows warm and your house stays comfortable, contact us at Hansberger Refrigeration and Electric Company. We provide Yuma with quality heating and cooling solutions.