Why Exactly Is My Furnace Blowing Cold Air?

Why is my furnace blowing cold air?
This isn't a question you want to find yourself asking in the middle of winter. Being stuck without heat can make being cooped up inside during COVID-19 even more challenging (and miserable!).
That's why we've put together this guide to help you figure out the problem and learn how to fix it, so let's get started!
Your Thermostat Is Set to "On"
Start by checking your thermostat. You may just have it on the wrong setting. As obvious as this might seem, it's a simple mistake many homeowners overlook.
For example, you want your thermostat set to "auto" rather than "on". If you leave your thermostat at "on", the fans will blow continuously, even when the heater turns off. This will cause them to push cold air through your vents when you don't want it.
The Air Filter Is Dirty
If your furnace overheats, it has a safety feature that'll make it shut down. A dirty filter restricts the airflow, which often leads to overheating. This means your furnace stops warming the air, but the fan keeps going, blowing cold air in your house.
Take out the old filter and replace it with a new one. If you don't have a different filter, do your best to at least clean off the dust and debris. This might keep your furnace running for a few more days until you can switch out the filters.
There's Something Wrong Inside the Unit
There are a number of other things that can go wrong inside your furnace that'll make the heater shut down. Some of these include:
- Clogged condensation drains
- Ignition system failure
- Faulty pilot light
- Limited gas supply
- Dirty flame sensor
- Etc.
You'll need professional help to fix these problems. If replacing the filter doesn't work, you should call an HVAC technician to take a look.
Your Ductwork Is Damaged
If your ductwork has a crack or hole, all the hot air can be escaping into your walls. By the time the air comes out the vents, it will feel much colder.
Again, you may not be able to find or reach the cause of the problem without the right tools. Get in touch with a heating company and let them patch up the ductwork for you.
It's Still Heating Up
Do you feel cold air coming out of your vents right after you turn on the unit? That's normal. Your furnace needs some time to heat up.
As long as the air gets warm after a few minutes, there's nothing wrong with your system!
Why Is My Furnace Blowing Cold Air? Solving the Mystery
Is your furnace blowing cold air? You should reach out to a professional HVAC technician and fix the problem now. The weather is about to get a lot colder, and you won't want to be stuck without a furnace during the winter.
Want to learn some other helpful ways to get your home ready for winter? Make sure you take a look at the rest of our blog today!