Why is My Furnace Blowing Cold Air?

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Why is my furnace blowing cold air?

As close as we are to summer, there are still some chilly, rainy days where you may want to have your furnace turned on. The last thing you want to find is that instead of blowing a comforting warm air, it’s blowing cold air instead!

We know how frustrating it can be dealing with a malfunctioning furnace, especially right at the time you need it the most.

Luckily, there’s no need to panic. As bad as the situation may seem, the solution could be a simple fix. Here are five common reasons a furnace may be blowing cold air and how you can resolve each situation.

1. The furnace isn’t warmed up

If you feel a blast of cool air when you first turn your furnace on, give it a couple of minutes to see if the air eventually gets warmer.

It’s normal for cool air to emerge from the vents at first since the furnace has to warm up. It’s the exact same as when you turn on a faucet for hot water but you get cold water at first.

2. Your thermostat is set to “On”

This is more of a common reason than you might think. If you notice a constant flow of cool air coming from your furnace, check your thermostat to see if the unit’s fan is set to “on” or “auto.” If your thermostat is set to “on,” your furnace blower will constantly run even when your furnace isn’t actually heating the air.

By switching it to “auto” the fan will only blow when the furnace is heating the air.

3. The flame sensor is dirty

Pilotless ignition furnaces use a flame sensor to keep the furnace burning once it starts. If that flame sensor is dirty, your furnace will turn on and begin heating but then turn cold relatively quickly.

If you’re familiar with furnace components you can most likely clean the sensor yourself. However, if you’re not comfortable performing that task you can always call us and one of our HVAC technicians will be happy to clean it for you.

4. The pilot light is out

If you have an older furnace and it’s blowing cold air, chances are the pilot light has gone out.

Feel free to follow the manufacturer’s instructions for how to re-light it safely if you feel comfortable doing so. If not, again, please contact us and we can assist you.

5. Your air filter is clogged

Dirty air filters can cause a lot of issues because they limit airflow into your furnace. Restricted airflow can cause your furnace to run longer to heat your home until it overheats. Once it overheats, you will only get cold air.

The solution is pretty obvious for this situation – replace your dirty air filter with a clean one. Once the airflow is no longer blocked, your furnace will be less likely to overheat and should function normally.

If you’re still having problems after all of these troubleshooting efforts, something more serious may be happening with your furnace.

If you live in the Brantford, Hamilton or Kitchener regions, the HVAC professionals to call are Crystal Heating and Cooling. Your Crystal technician will work through a series of tests to pinpoint the exact source of trouble and get your heating system up and running again as soon as possible.

Frequently Asked Questions:

Which furnace filter is best?

A furnace filter provides protection for your HVAC system, while also enhancing air quality inside your home. Made from various fibers, including fiberglass, polyester, or cotton, these air filters work by capturing particles like dust, dirt, and dander that would otherwise clog up your furnace or settle in your ductwork. There are many types of furnace filters to choose from, depending on your objectives for air quality and how often you want to replace the filter. The filter material plays a role in the lifespan of the filter and determines how efficient the filter is at capturing particles. To find the right filter for your needs, the industry-standard rating system is MERV. It ranges from 1 to 20, with average residential furnace filters receiving MERV scores between 5 and 10. The higher the MERV rating, the fewer particles that can pass through but will also require your filters to be changed more frequently. To eliminate worries and confusion, you can always sign up for our air filter subscription program.

How often should you clean your furnace?

It is recommended to have your furnace cleaned once a year by an HVAC professional. A clean, well-adjusted heating system will save you money in energy costs and prolong the life of the furnace. Some signs that your furnace needs a cleaning are unusually high energy bills, yellow furnace flames, and your furnace making loud noises.