Why Is My Heater Blowing Cold Air?

Woman sitting on the couch covered with the blanket shivering because heater is blowing cold air.

Coming home to a broken heating system is probably not what you meant when you wished for a winter wonderland. But don’t worry! If you don’t know what to do when your heater is blowing cold air, the experts at Tempo Air are here to help! 

Here are the top five issues causing your heater to malfunction and how to fix them. 

Dirty Air Filters

If your heater is blowing cold air, why not start with the most common problem—a dirty air filter?

Air filters are your furnace’s first defense against dust and debris. While your heater is hard at work keeping your home warm and cozy, the filter traps any particles circulating in the air ducts. If not replaced on a regular basis, it can become clogged. This not only invites debris inside your heating system but also causes the unit to work harder to produce the same amount of heated air.  

When a dirty air filter is the reason why your furnace is blowing cold air, make sure to replace it as soon as possible. You should also schedule a service with a professional HVAC company to remove any debris found within your unit. Enough dust buildup will cause the internal components to overheat, trigger your furnace’s limit switch, and lead to a system shutdown. 

Wrong Thermostat Settings

The easiest thing to do if your heater is blowing cold air is to check the thermostat. Problems with the thermostat are quite common and can easily be fixed without the help of a heating expert. 

Is Someone Changing the Temperature?

When everyone in your family has different comfort levels, it can be difficult to agree on one thermostat setting. So, is someone going behind your back to adjust the temperature? Check to make sure the thermostat wasn’t set to cool mode accidentally (or on purpose). 

Is Your Fan Set to Auto?

Your thermostat has two fan settings: auto and on. Auto is the preferred setting—it means your fans are only running during a heating cycle. However, when the fans are on, they run continuously to circulate air throughout the room. This is why you feel cold air blowing from the vents even though the heat is on. 

Furnace Needs Time to Warm Up

Unlike your car heater, which can have your surroundings feeling like a sauna within minutes, your residential HVAC system takes time to warm up. 

It’s not uncommon to experience warm fronts in our area, even during the winter months. If you recently turned off your heating system to enjoy the beautiful weather and are now restarting it for the first time in a few days, just know that may be the reason why the heater is blowing cold air. Your furnace is a complicated machine and needs to thoroughly warm up before distributing heated air. 

Wait about 10-15 minutes for everything to kick into gear. Otherwise, calling a professional is the only thing to do if the heater is blowing cold air still. 

Tripped Breaker

Another reason why your heater is blowing cold air is a tripped breaker. Check to make sure everything is working properly in the circuit breaker box. Additionally, unplug your heater and test the outlet itself. Whether your own an electric, oil, or gas furnace, all units need to be connected to electricity to run. 

Mechanical Issues

Still not sure why your heater is blowing cold air? You might have a mechanical issue. This refers to any problems with the internal components apart from the furnace filter. Whether your gas supply is low or a flame sensor is broken, mechanical issues should only be handled by the pros. 

Not sure what to do if the heater is blowing cold air and you can’t fix the issue on your own? It’s time to contact an HVAC technician! 

Tempo Air is an employee-owned HVAC company dedicated to providing the leading heating repair services in Irving, TX, and beyond. Contact us to schedule a service!

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