How Often to Change Furnace Filters?

Today, we’re diving into a topic that’s crucial for maintaining the optimal functioning of your heating system: your furnace filter.

We often overlook this component, but did you know that your furnace filter plays a vital role in not only maintaining your indoor air quality but also affecting your energy costs?

In this article, we’ll break down everything you need to know about furnace filters, including why they’re so important, how often you should change them, and what could happen if you don’t.

How Often to Change a Furnace Filter?

A common question homeowners often have is: how often should I change my furnace filter? The answer to this depends largely on the type of filter you have, but a general rule of thumb is every 1-3 months.

However, thicker filters, like 4-inch or 5-inch filters, can typically last longer. Factors such as the presence of pets, the type of air conditioner you have, and the specific air quality in your home can also affect how often you need to change your furnace filter.

Steps to Change Your Furnace Filter

  1. Turn off your HVAC system.
  2. Locate the filter cover and open it.
  3. Remove the current filter.
  4. Check the size and type of the current filter.
  5. Insert the new filter, ensuring the airflow arrow points towards the blower motor.
  6. Replace the filter cover and turn your HVAC system back on.

Why is Changing a Furnace Filter Important?

Furnace filters play a key role in maintaining the indoor air quality in your home. They trap airborne particles like dust, pet dander, and other airborne contaminants, preventing them from circulating in your air and causing issues like allergies. Additionally, a clean filter ensures your furnace runs efficiently, which can lower your energy costs.

Can You Wash Your Furnace Filter?

While some types of filters, like washable filters, can be cleaned and reused, most common types like fiberglass filters or pleated filters are disposable and need to be replaced.

What Does a Furnace Filter Do?

A furnace filter traps airborne dust, dirt, and other particles from the air before it enters the furnace’s heat exchanger and air handler.

This prevents these particles from circulating through your home and also protects your furnace’s vital components.

Factors That Affect How Often You Change Out Furnace Filters

Several factors can influence how often you should change your furnace filter. These include:

  • Type of filter: Some filter types like pleated air filters can last longer than others like fiberglass air filters.
  • Presence of pets: Pets can produce more dander and hair, which can clog your filter more quickly.
  • Indoor air quality: If your home has poor air quality or someone in the household has allergies, you may need to change your filter more frequently.

What Happens if You Don’t Change Out Your Furnace Filters?

Not changing your furnace filter regularly can lead to a build-up of dust and other airborne particles, which can negatively impact your indoor air quality. It can also make your furnace work harder, increasing your energy costs and potentially causing damage to your furnace.


Taking care of your furnace filter is crucial for maintaining the health of your HVAC system and your home’s air quality. By understanding the role of the furnace filter and remembering to replace or clean it regularly, you can enjoy cleaner air, lower energy costs, and a longer-lasting furnace.

Always remember to check your filter monthly and replace it as needed to keep everything running smoothly. And as always, when in doubt, reach out to a professional HVAC technician for help!

About Roy Cohen

Roy Cohen has a burning passion for heating, cooling, and ventilation. He aims to help you save money on expensive repairs and bring you the best HVAC products. He has years of experience behind him in HVAC repair and garage maintenance.

You can find Roy at his LinkedIn or his email: [email protected]

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