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How Often Should You Change Your Furnace Filter?

Many AC/Heat systems have air filters, including furnaces. Although it’s easy to overlook, this filter plays an important role in your heating system’s overall performance and longevity, as well as your home’s indoor air quality and comfort.

So, how often should you change your furnace filter? Although there is a general rule of thumb that you can follow, you should know that there are many factors, such as filter size, that can influence how often you perform this simple maintenance task.

It can be challenging to know how often to change furnace air filters, especially when it comes to your specific needs. Fortunately, this guide will make it easy to find the right solution for you.

How Often to Change Furnace Air Filters

If you want to know how often you should change your furnace filter, it’s crucial to start with the basics. As a general rule of thumb, many AC/Heat technicians recommend replacing the filter at least once every 90 days.

Of course, how often you replace your filter will depend on many factors. For starters, you’ll want to have a thorough understanding of the types of filters out there. Thinner filters will likely need to be replaced on a more frequent basis, while thicker filters can wait a while. For example, you should replace 1 to 3-inch filters every two months, while 5-inch filters can typically be changed every 12 months.


Do you have many furry friends living in your home? If so, this can affect how often you should change your furnace filter. You’ll likely want to consider changing the filter every six weeks. Although pets bring so much joy to our daily lives, they can leave behind pet dander — harmful airborne pollutants that can worsen allergies and asthma.

When you replace your filter more frequently, you can prevent dander from circulating through your home.


If you have allergies, you know how important it is that your home has good indoor air quality (or IAQ). Unfortunately, a clogged or dirty air filter can negatively affect your IAQ, potentially leading to sniffling, sneezing, and other respiratory problems.

If you’re unsure how often to change furnace air filters when you have allergies, just know: the sooner, the better. All-in-all, you’ll most likely want to replace the filter once every six months.


Is your home excessively dusty? If this is the case, you’ll certainly want to replace your furnace filter more frequently. If you have a thinner filter, it’s a good idea to change it every month or so. If you have a thick, 5-inch filter, you can typically replace it about every three months.

What Happens if You Don’t Change Your Furnace Filter?

Now that you know how often to change furnace air filters, you might still be wondering: why is this important? When it comes down to it, a dirty, clogged filter can lead to many unwanted problems, including high energy bills, poor indoor air quality, and overall discomfort.

If the filter becomes dirty or clogged, the airflow coming and going to your heating system will be negatively affected. When this happens, the furnace will need to work harder to meet your heating needs. This can end up wasting a significant amount of energy and lead to higher energy costs.

Although high energy bills are some of the most common signs your furnace filter needs changing, it’s not always so obvious. It’s important to take a look at your specific needs to find the right solution for your home.

Schedule a Heating Tune-Up With Our Experts

How often should you change your furnace filter? If you ask several technicians this question, you’re likely to receive a wide variety of answers. Fortunately, with this guide to help you, you should now have a better understanding of what your heating system requires.

Did you know that replacing the air filter is only one of the many maintenance tasks your furnace requires? Your heating system needs annual maintenance and care to ensure it’s running smoothly and efficiently. If it’s been a while since you last scheduled a heating tune-up, get in touch with Rite Way Heating, Cooling & Plumbing.

Our heating and cooling experts offer a wide range of services, including installations, repairs, and maintenance. We’re proud to have the skills and experience to help your air conditioner or furnace run at peak performance. Whether you need an AC/Heat system maintenance service or duct cleaning in AZ, feel confident that our team is the one to call.

Don’t neglect your heating maintenance needs. Contact us today to learn more about our tune-ups!