Is your home not heating or cooling as it used to? You may need to install a new HVAC filter. HVAC filters play a crucial role in the efficiency and longevity of your heating and air conditioning system and in improving your home’s air quality. Regular replacements can significantly benefit your family’s comfort, health, and energy bill.

If you haven’t changed your HVAC filter in a while, it could be making your system work harder than necessary—driving up your utility bills and potentially even freezing up your system. Thankfully, replacing a dirty filter is a simple process. Keep reading to learn how to change air filters in four steps.

1. Turn Off the Power

Safety first! Before you start the HVAC filter replacement process, turn off the power to your unit. This typically can be done by flipping a switch on the side of the unit, but if you’re unsure where to find the power switch, you can consult your owner’s manual.

Note: If your filter is located in a return air duct, you can skip this step.

2. Locate the Filter

If you’ve started the process, you may wonder, “where is my HVAC filter?” Filters are usually located in the return air duct or in the blower compartment of your unit. Locate your filter to remove it and replace it with a new one.

Note: Some units have front panels that pop off, but others require tools like a screwdriver or wrench to remove them. Consult your unit’s manual to ensure you’re equipped with the right hardware before starting.

3. Remove the Old Filter

Carefully remove your old furnace or air conditioner filter—be sure not to drop or jostle it too much, as this can release dust and allergens back into the air. Take note of the arrows on the filter’s edge, as they will tell you which way to insert your new filter in the next step. Also take note of the size of the air filter so you purchase the correct replacement filter.

Image shows dirty air filter with red circle around size of filter for replacing it.

4. Insert Your Replacement Air Filter

To install your new filter, ensure the arrows on your new filter are facing the same direction as the old one—typically the direction of the airflow. For a ceiling-mounted filter, arrows generally face up. For a filter next to your blower, arrows generally point toward the blower, filtering air before it enters the unit.

Note: If you can’t remember which way to put HVAC filters into your unit, look at your manual or search for your unit’s model online.

Once you’ve completed these steps, close your unit and turn it back on. (Once again, if your filter is located in a return air duct, you can skip powering it off and on.) You may notice stronger airflow after replacing your filter, and dust in the air should begin settling as your new filter does its job.

How Often to Replace Air Filters

Most standard 1-inch air filters have a 3-month lifespan, but this can be shorter depending on a few factors.

Pets: Our beloved animals create a lot of fur or hair, dander, and dust around the house. If you have pets, scheduling more regular heating and AC filter replacements is a good idea.
Allergies: Special filters may require more frequent replacement to adequately remove allergens from your home.
Climate: If you live in a hot or humid location and run your system continuously, you may need to change your filter closer to once per month.

What Size Filter Should I Buy?

After removing your HVAC filter, you can check its dimensions, as you’ll need to buy a new filter matching its size. Most filters have this information clearly printed on an edge, but if it’s missing, grab a tape measurer and take note of each measurement, or check your system’s manual to determine what filter size it can take.

How to measure HVAC air filter

How Does Your Heating or Air Conditioner Filter Work?

As your furnace or air conditioner moves hot or cold air throughout your home, the air filter catches dust, pollen, pet dander, and other particles. This ensures only clean air is pumped back into your home. When the filter becomes clogged, it can block airflow and force your HVAC system to work overtime—using more energy or even causing your unit to malfunction. A dirty filter also allows contaminants and allergens to build up in your home—posing potential health threats to you and your family.

Related: How Air Conditioners Work

Air Filter Replacement Tips

Keeping track of when you last changed your filter can be a challenge. Try one of these tips to remember more easily:

Write the date on the edge of your new filter before you insert it, so you can keep track of when you last changed it.
Sign up for a service that ships you new filters at one-, two-, or three-month intervals.
If you change your filter monthly, use your utility bill as a reminder and replace your filter every time your bill arrives.

Be prepared for unexpected HVAC issues with home warranty coverage from First American. Choose from plans and upgrades that help provide peace of mind by covering heating, ductwork, central air conditioning, electrical systems, and more from breakdowns due to normal wear and tear. Request a free home warranty quote today to learn more.

The contents of this article are provided for general guidance only. First American Home Warranty does not assume any responsibility for losses or damages as a result of using this information.

Please be aware that if you disassemble a covered system or item, it can invalidate your home warranty or manufacturer's warranty.