The last thing you want on a chilly winter day is to have cold air blowing out of your furnace. HVAC units often have to work harder in extreme weather. That overexertion can cause issues requiring furnace repair. Below are a few possibilities of what’s causing the trouble.

Why Is Your Furnace Blowing Cold Air?

1. Switched On Thermostat Fan

Is there an intermittent gust of cold air coming from your vents, even when the furnace is running? If yes, the thermostat’s fan is likely on, making the blower circulate air throughout your home. Check the thermostat for the fan settings—you may have to switch it to “AUTO” so it will only blow air when the furnace operates.

2. Clogged Air Filters

Furnaces come with filters to trap airborne dust, dirt, and other debris. Clogged air filters make your furnace run less efficiently, shorten its lifespan, and can also lead to cold air running through your home. They obstruct airflow from the heat exchanger, causing it to overheat. This trips the high limit switch to stop the heat exchanger from cracking, leaving you with unheated air. Have a furnace repair technician reset the unit and change the filter.

3. Unlit Pilot Light

Some furnaces have a standing pilot light to start the unit. But when it goes out, the burners won’t heat the air, resulting in cold indoor temperatures. A furnace repair specialist should re-light the pilot light to check the ignition for other possible issues, such as a faulty thermocouple or clogs in the appliance.

4. Dirty Flame Sensor

If your furnace doesn’t have a pilot light, it probably has a flame sensor to keep the unit burning. If it cannot detect a flame, it automatically shuts down the gas pipe as a safety precaution. Without gas, there’s nothing to heat your home, leaving you with cold air.

If your heating unit continues to blow cold air, better call for furnace repairs. For prompt service, turn to Glorieta Creek Mechanical, a full-service HVAC contractor in Santa Fe, NM. They’ve provided expert residential heating repairs and maintenance, as well as plumbing and water heater services since 2006. Call (505) 757-8872 to schedule emergency service or visit them online today.