3 Reasons Why Your Furnace is Blowing Cold Air

Cool air blowing from your vents is certainly welcome on warm summer days, but definitely not in the middle of a cold Mid-Atlantic winter day or night. Whether your furnace is an older model or more modern, a little troubleshooting may be all you need. So, before you call your HVAC professional, check these three common reasons furnace cold air is blowing from your air vents.

Check Your Thermostat

You’ve probably already checked your furnace’s thermostat, but take a look at it one more time. Make sure that it is in “heat” mode and that the temperature setting is higher than room temperature. Set the thermostat to “auto” and not to the “on” setting. The “on” setting makes the blower run continuously whether or not the furnace is heating.

Check Your Filter

A dirty air filter makes your furnace use more energy, stresses the blower motor and contributes to poor indoor-air quality. A clogged filter can also cause your furnace to overheat and shut down the flame. Check your air filter. If it’s dirty, replace it. Keep enough good air filters on hand to last until summer.

Ignition Problems

Problems with fuel ignition will certainly prevent your furnace from blowing warm air. If you have a very old furnace, it may use a standing pilot light. Check to see if it is on. Drafts and dirty burners can cause the pilot to go out or not be able to ignite the gas.

More modern furnaces use electronic ignition, such as hot-surface igniters. These devices tend to last three or four years before they fail. It’s wise to keep an extra one in your home in case your old one fails in the middle of the night. Changing this device yourself, if possible, will save you a service call for furnace cold air blowing from your vents.