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Why Is My Heater Blowing Cool Air?

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As the season starts getting colder, you’ll want to start using your heater regularly to keep your home nice and warm. If you’re finding that your heater is doing the exact opposite of what it’s supposed to do, there are a few things you might want to check. Use the troubleshooting tips below or contact us for help from an expert! 

Time for a Tune-Up?

Give It Time To Warm Up

We’d all love for our home to reach a cozy 75 degrees immediately when it’s 20 degrees outside, but this isn’t feasible. Give your heater roughly five to 10 minutes to warm up. Old heating units will need a bit of patience when heating up your home for the first time since the last cold season.

Check Thermostat Settings

For several reasons, a thermostat can be the culprit of your heater blowing cold air. If you happen to have a smart thermostat, an accidental tap on the screen can cause it to adjust to a lower temp setting. Similarly, it can accidentally be set to “on” instead of “auto.” This would result in your heater’s fan blowing even though your furnace isn’t heating the air. Additionally, it’s always possible that your thermostat may have been left at a setting used for spring and summer and hasn’t yet been changed for fall and winter. 

Pilot Light May Be Out

Older furnaces typically use a pilot light to heat up air before it gets circulated throughout your home. So if your heater is blowing out cold air, it could be that the pilot light in your furnace may be out. Your furnace should’ve come with an instruction kit to guide you on how to relight the pilot light, but proceed with caution. The pilot light is fed continually from a gas line so be sure to follow the kit’s instructions to the letter or call in a professional.

Make Sure Flame Sensor & Filter Are Clean

A dirty flame sensor makes it impossible for your gas burner to stay lit, preventing your heater from heating up the air. Likewise, dirty filters prevent heated air from entering your heater’s chamber to get heat up before moving throughout your home. While swapping out a dirty filter for a new one is a relatively easy task, cleaning a flame sensor requires much more expertise to prevent your unit from being damaged. Contact Suburban HVAC and we’ll send one of our expert technicians to address your concerns.

Outside Unit May Be Covered

If you’re using a heat pump, it’s possible that the component outside your home may be covered with snow, ice, or heavy debris. This is an easy fix that requires simple cleaning. However, for more serious cases such as low refrigerant and wear and tear, you’ll need the help of a professional.

Mechanical Failure

If none of the troubleshooting tips above resolve the issue, then it’s safe to assume that there’s a more severe underlying issue with your heating unit that may require repairs. Attempting these repairs on your own can cause you harm and lead to irreparable damage to your unit, resulting in even more costly repairs or a full replacement.  

At Suburban, we offer high-quality residential heating repair services for:

If you’re having trouble with your heating unit, call on Suburban and we’ll get it fixed up in no time! Call us at 781-769-1515 or contact us online.


Should I switch out my furnace for a heat pump?

Heat pumps are best suited for areas that don’t experience extremely cold weather and can be a highly energy-efficient alternative to traditional heating units. They also have a long life span. It’ll all depend on your preferences and needs.

Why is my heater making noise?

It’s possible that something is interfering with airflow, debris buildup, or a faulty part in your heating unit. A professional would be able to diagnose the issue, find the cause, and get it squared away. 


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