It’s cold outside, and it’s the same temperature in the house, YIKES! It’s far from the norm to feel cold air coming from a furnace, while in Heat mode . When you do, the cause may be a simple fix or an issue that requires a Certified McKee Bros technician. Before you call McKee Bros, ask yourself a couple questions like  “Why is the air from my furnace cold?” try some DIY solutions first and hopefully save making a service call.

Troubleshooting Tips *Furnace Blowing Cold Air

Overheating and Air Filters

A clogged, dirty air filter may reduce most heating equipment’s ability to warm a home effectively & efficiently. If the equipment has to work overtime to make your home feel comfy, this may cause your system to overheat and shut down the burner, making it seem as if cold air is blowing into your home.

Has it been more than a month since you lasted changed the filter? Let’s start there first, and change  furnace filter Asap. After changing filter,  now restart the furnace and continue to replace the filter on a monthly basis. (TipKnow your furnace filter size and buy a few to keep on hand)

Thermostat Batteries

When the batteries in a thermostat need to be changed, your heating equipment may not operate properly. If your thermostat works on batteries alone, instead of being connected to your home’s central power, try replacing your batteries ASAP.

Thermostat Mode

Thermostats have two modes: Heat & Cool. During the cooler months of the year, make sure the thermostat is set to “Heat” mode to prompt your heating system to warm your home. When the weather warms up, switch it to “Cool” mode, unless your home doesn’t have air conditioning.


Thermostat Temperature Setting

If you still feel cold air coming from the furnace after verifying the thermostat is on“Heat” mode, check the temperature. The set temperature on thermostat should be warmer than the room’s temperature. Try increasing the temperature 5 -10°F and see if that makes the difference.

Thermostat Fan and Limit Switch Setting

If the fan continuously blows, it may send cold air into your home even when your heating equipment finishes cycling. If the fan is set to “On,” switch it to “Auto.”

If the thermostat fan setting is on “Auto” and the fan continues to blow, check the furnace’s limit switch. You’ll find the limit switch under the furnace hood (See picture) . Like the thermostat, the switch should be set to “Auto” instead of “On” or “Manual Override.” If the switch’s button is depressed, pull out button and switch it into “Auto” mode.


Air Duct Leaks

It’s very common for ductwork to develop leaks over time. When ductwork has a leak, cold air will enter a duct and blow into your home. At the same time,  the warmer air will escape through the leak and enter the unoccupied space. * You may notice that your homes dustier and more humid than normal.

If you feel cool air coming from your furnace and the previous troubleshooting tips haven’t helped to mitigate the problem, there just may be a leak in your ductwork.  Quick fix* Try applying Mastic or Foil Tape designed for ductwork and apply the tape directly over the leak, as long as you’re able to locate the leak safely. Still not working, call McKee Bros to diagnose your heating equipment and ductwork.

Electronic Control Panel

*SIMPLE FIX* Newer furnaces have electronic control panels that may act up from time to time. Try resetting the system by turning the furnace off at the power switch, and then switch furnace back on after a few minutes. This may solve your issue.

*A long list of issues from faulty ignitions to OUT OF OIL, can leave you wondering, “Why is my furnace blowing cold air?” If our simple troubleshooting suggestions hasn’t resolved your heating problems, it’s time to call McKee Bros .  Our HVAC professionals are trained to quickly locate the problem and fix your heating /cooling system, so you don’t have to spend a minute longer in a cold home. If your heating/cooling equipment isn’t performing as effectively as it should, schedule an appointment with McKee Bros today.