Why Is My Furnace Blowing Cold Air?

So, you’ve just come home from one of the longest, most exhausting work days yet, only to discover your furnace is blowing cold air. Before you panic or conclude that karma’s out to get you, we recommend trying to troubleshoot the issue. Sometimes what seems like a lost cause is actually just a minor problem that can easily be fixed. Here are 3 troubleshooting methods to try before calling a licensed professional.

  1. Check Your Thermostat Fan Settings

Your thermostat fan has two settings: “on” and auto.” This setting controls the unit’s blower, which distributes air throughout your home. It’s not uncommon to accidentally adjust the thermostat fan settings; in fact, everyone does it at one time or another. Take a look at your thermostat to ensure the fan is set to “auto” rather than to “on.” If it’s in the “on” position, it means the blower has been running 24/7, which is why you’re feeling cold air at certain times.

  1. Change Your Dirty Air Filter 

Unfortunately, because air filters are out of sight, they’re often out of mind. When you have a dirty, clogged air filter, it can lead to numerous problems, some of which can be very costly. If you have a filter that has stayed way past its welcome, it will often cause air flow restriction and overheating. A system that’s overheated will blow only cold air. To prevent this from happening again, replace your HVAC filter on a regular basis. Refer to your manufacturer’s guidelines on how often you should change out the filter.

  1. Check the Pilot Light

If you have an older gas furnace, the source of the problem could be your pilot light. When the pilot light goes out, your furnace can’t blow hot air because the burners aren’t lit. Before you attempt to light your pilot light, we recommend watching this step-by-step video and carefully following the steps. If you’re not comfortable completing this task yourself, call a licensed HVAC technician to do it for you. It’s far better to err on the side of caution than to potentially endanger yourself. Before you begin, make sure your heat is turned off. If your pilot light won’t light or it won’t stay lit, call a technician right away, because you likely have a faulty thermocouple that needs to be replaced.

Is Your Furnace Still Blowing Cold Air? 

If you weren’t able to troubleshoot your furnace, you likely have a bigger problem on your hands, one that requires the expertise of an experienced technician. Here are several possible reasons why your furnace is still blowing cold air.

  1. Leaky Air Ducts – If there are holes or gaps in your ductwork, all the cold air from your attic or crawlspace could be the culprit. In this case, you need to have an HVAC technician inspect your ductwork to determine the extent of the problem and how to best repair it.
  2. Not Enough Gas – When your furnace doesn’t have an adequate supply of gas, it will lock down. Check to see if your gas supply is off. If it isn’t, then you likely have a severed line, at which point you will have to call a professional.
  3. Dirty Flame Sensor – Similar to a dirty, clogged air filter, a dirty flame sensor can also lead to heating problems. When your flame sensor is covered with grime it can’t light your burner. This is just one of the many reasons why you need to schedule routine maintenance for your HVAC equipment. During your visit, our technician will ensure all parts of your system are clean and in working order.

If you’re still asking, “Why is my furnace blowing cold air?” then give the trusted experts at Bardi a call! We’re here for you 24/7 to address all your heating, cooling, and plumbing needs. Schedule your appointment today by calling (770) 263-9300.


Article Categories