With winter weather in full swing in Boston, it’s safe to assume you’re relying on your furnace to keep you warm. While you expect your furnace to provide efficient service, you never know when something could go wrong. For example, just as you’re settling into bed for the evening, you realize that your furnace is not blowing hot air. A furnace blowing cold air is a big problem, so it’s important to pinpoint the issue and resolve the problem as soon as possible. Here are three of the most common reasons for this:

1.  An Issue with Your Thermostat
If you have an issue with your furnace blowing hot air, this is typically the type that you want. You can solve many thermostat related issues on your own, including the following:[i] The thermostat is set to cool: Maybe someone in your house, such as a child, did this by mistake. Or maybe you clicked the wrong button when attempting to turn up or down the heat. Either way, make sure your thermostat is set to heat.

The fan is set to “on” instead of “auto”: Your furnace is not designed to blow an unlimited amount of hot air. At some point, the fan will begin to blow cold air. Since you don’t want your furnace blowing cold air during down time, be sure it’s set to “auto.” Low or dead battery: If you have a digital thermostat, it’ll tell you when the battery is low. If you neglect to swap it out for a fresh battery, it can cause problems regarding how your furnace operates. If your furnace is blowing hot air, your thermostat is the first thing you should check. You may find a simple solution to your problem.

2.  Clogged Furnace Filter
When was the last time you changed your furnace filter? If you can’t remember, there’s a good chance it’s been too long. And if your furnace isn’t blowing hot air, this could be the culprit. A furnace filter is designed to protect the unit from debris, such as allergens, dust, and hair (and that’s just the start).[ii] Without this, your blower fan would come in contact with all types of materials that could impact performance and shorten its lifespan. An old, dirty filter is unable to do its job as intended, which can result in stress on your unit. And too much stress can cause the burner to overheat, which will result in it blowing cool air into your home.

Fortunately, this is an easy problem to fix, as long as the old filter didn’t cause any damage to the furnace itself. All you have to do is swap out the old filter for a new one and restart your furnace. After a few minutes, you should once again experience a steady flow of hot air throughout your home’s ducts.

3.  Burner Related Issues
There are many parts of a furnace, with the burner among the most important. Since it’s vulnerable to dirt and debris, there’s a chance a clog could prevent fuel from reaching it. If this happens, your fan will still blow, however, cold air will come from your ducts. This isn’t a DIY fix, as your safety and the well-being of your burner is at risk. It’s best to call in a professional who can diagnose the problem, clean the burner, or replace it if necessary.

Need Furnace Maintenance?

At Boston Standard Company, the last thing we want to hear is that your furnace is not blowing hot air during the cold winter months. But if you run into this problem – or any other – don’t hesitate to contact us. We can visit your home, troubleshoot for the issues above (among others), and provide a timely and cost-effective solution.
[i] https://www.familyhandyman.com/heating-cooling/furnace-repair/simple-furnace-fixes/
[ii] https://globalnews.ca/news/1621011/what-you-need-to-know-about-furnace-filters/


Skip to content