What Happens If You Don't Change Your Furnace Air Filter?


Dear Any Hour,

Is it really necessary for me to change the air filter on my furnace? What happens if I don’t do it? And how often should I really be doing it?

- Michelle S.

Ask Any Hour - what happens if you don't change your furnace air filter

The short answer is YES, it is necessary for you to replace the air filter in your HVAC unit (furnace & AC) all year round. When it comes to getting the most out of your furnace and maintaining your utilities -- checking and changing your air filter is very important. The filter collects dust and debris that might otherwise go into the furnace and cause problems. It does this job pretty well, but it has one major drawback: it can’t get rid of the debris that it collects. This is why the filter needs to be replaced every 1-3 months.

What Happens If I Forget To Change the Filter?

The last thing you want is for your furnace filter to look like the picture. You should change your filter every 1-3 months, depending on such variables as the type of filter you have, if you have pets in the home, and how much your furnace is operating. Why is this necessary, and what happens if you don’t change your furnace filter?

  1. Safety Concerns - Dirty filters can cause several safety concerns like clogging, overheating, fire starting, and short cycling (causing your furnace to turn off).

  2. Poor Air Quality - The purpose of the air filter is to catch and reduce the amount of dust, pet hair and other allergens in your home. Having air run through a dirty filter can increase, rather than reduce, these allergens and can cause adverse reactions to people in your home. Oftentimes the air outside your home is much cleaner than your indoor air, which can be concerning especially to those already living in poor air quality areas or those suffering with allergies and breathing conditions.

  3. HVAC Unit Lifespan - If the air filter isn’t replaced often enough, it will eventually become clogged to the point that air cannot pass through it. When the furnace is operating, the lack of airflow will trap the heat in the system. As the temperature inside the system continues to rise, the limit switch will activate and shut down the furnace to prevent it from overheating. This will temporarily mitigate the issue, but it won’t solve the root problem. Without a new air filter, the furnace will overheat every time it starts up again. This is referred to as short cycling.

    Dirty furnace filters cause your furnace to work harder than it should due to a decrease in airflow. The harder your furnace works, the quicker its parts will wear out and need repairs. In the long run, this will shorten the life of your HVAC unit.

  4. High Energy Costs - Because your furnace works harder with a dirty filter, it will run longer and more often. This increases your energy costs during the winter, as your furnace struggles to keep your home warm.
When Should I Change My Furnace Filter?

The simple answer is -- when it gets dirty. The tricky thing is that every person’s system is different. Often, people rely on a random “when it feels right” approach. Until you figure out how long your filter will last before needing to be changed, we recommend by starting by checking it every month. Take it out, hold it up to the light. If you aren’t seeing enough If you can still see light through it, reinstall it and check it the next month. Eventually, you will learn how often you will need to change your furnace filter. Some people need to change theirs every month while others can change it every 4 months.

Not only does changing your filter make your house’s heating and cooling better, it also saves a little money on your utility bills. Whether you don’t know how to replace your air filter, or how often to do it, following these easy steps will guide you through the process.

Many people don’t realize that their furnace has an air filter. What’s important is that you take proper action now to keep the filter in good shape. If you don’t, you could find yourself spending thousands of dollars in repair and replacement costs years earlier than you otherwise would have to.

You can save yourself quite a bit of frustration if you remember to check your air filter every month and replace it every few months. This prevents it from becoming clogged and making your furnace work harder and causing issues. If you’re not sure where your air filter is located, call a professional and they would be happy to show you.

If you'd like to see how to check your filter and replace it, click here.

If you'd like to read more about Furnace Filters, click here.


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Author: Amber Smith-Johnson
Copyright © 2020 by Any Hour Services


Jan 15th 2020

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