Taking care of your HVAC system is essential to maintaining your house. One important task is replacing the HVAC filters regularly. This step-by-step guide is designed to walk you through the process of replacing air filters. 

The Importance of Replacing Air Filters

Before getting started, here’s a reminder why replacing your air filter matters. HVAC filters remove dust, allergens, and other particles for improved indoor air quality. Air filters in HVAC also help your system run efficiently by preventing clogs and reducing strain on the equipment. Replacing air filters regularly is an easy way to ensure cleaner air in your home and prolongs the lifespan of your HVAC system.

When to Replace Air Filters

You might be wondering how often to replace air filters?

This depends on your person usage and factors such as: 

  • Filter type
  • Indoor air quality
  • System usage

A general rule of thumb is to check your filters every 30 days and replace them at least every three months.

It could make sense to replace the filters every 1-2 months if you have pets, allergies, or have a house prone to dust.

What Size Air Filter Do I Need?

Start by checking the current filter. The existing filter in your HVAC system should, in theory, be the correct size. The size is typically printed on the frame and should be easily visible. Look for dimensions: length, width, and depth. The dimensions are usually written in inches. For example, 14" x 20".

Locate a measuring tape and measure the slot holding the filter. The filter should be a close fit. If the filter already inside appears close, then you can likely skip this step. 

Write down the dimensions to ensure you buy a proper sized replacement. 

When assessing options for filter replacements, consider filter type and quality. Air filters come in various types, including: 

  • Fiberglass
  • Pleated
  • Electrostatic
  • HEPA 

Choose a filter that suits your household’s specific needs. For example, if you have pets, you might want an air filter specializing in capturing pet dander.

Homeowners can opt to buy multiple filters at once to ensure replacements are on hand for future use. This also saves you the trouble of having to check the size each time the air filter needs to be replaced. 

What Tools Do I Need to Replace My AC Filter?

In preparing to replace air filters, you’ll want to have a few household items on hand: 

  • Screwdriver: most HVAC systems require one to gain access.
  • Vacuum: you’re likely to kick up some dust in the process. It’s a good idea to have a vacuum or handheld duster to help clean up.

Where is the Air Filter Located?

Before you install a new air filter, you’re going to have to find where the old one is located. In most homes, the air filter is located near the return air duct or in the blower compartment of the HVAC system. Check your system's manual if you're unsure. 

Safety Note: Make sure your HVAC system is turned off before proceeding.

Air Filter Removal and Installation Process

At this point, the HVAC system should be turned off. Be sure to turn the system off before opening the access panel or proceeding with installation. How to change the air filter should be fairly straight-forward. 


Remove the access panel. Take a moment to note which way it was facing. There are often arrows indicating which way is up. You’ll want to replace the panel correctly, which should be the way it was affixed in the first place. 

Take a moment for inspection. Clean the surrounding area. Additional cleaning can help maintain the air quality in your home as well as extend the life of each air filter replacement. 

Remove the old filter and dispose of it. Put in the new filter. Reattach the access panel with attention to accuracy. Securing the panel properly prevents air leakage. 

Set yourself a reminder to check the filter in 30 days. If the filter was still in usable condition, make a note of when you next expect to have to replace the filter. 

Don’t forget to turn the system back “On” after you have completed installation. 

When to Seek Professional Help

When you’re working on a home project, it’s important to know when to consult the professionals. If you’re concerned about properly changing your air filters, have no fear, we’re here for you. Our skilled HVAC Experts are here to talk you through the process in real-time. Simply download the Frontdoor app and your first video chat is free. . 

Reach Out to Frontdoor for Professional Assistance

At Frontdoor, we know you love getting things done around the house. Staying in control of your to-do list is easier when you can keep the small things from turning into bigger—and more expensive—ones.  Our HVAC, appliance, electrical, plumbing, and handyman Experts are here to answer your home repair and maintenance questions in real-time.They can also provide you with a list of local, vetted Pros from our network should you need in-home service. Frontdoor is here to fix how you fix your home. 

Frontdoor assumes no responsibility, and specifically disclaims all liability, for your use of any and all information contained herein.