The Ultimate Guide to Replacing HVAC Filters: Types, Timing, And Tips

Your furnace filters are an underappreciated part of your home systems. Although you might not think about them often, they’re responsible for protecting you and your loved ones from excess airborne dirt, dust, and contaminants that can spread sickness, disease, and other hazards.

That’s why HVAC filter replacement is so important. Since they work around the clock, they have a finite lifespan and should be swapped out to keep your family protected. 

But not all air filters are the same. Follow our guide on replacing HVAC filters to ensure you have an efficient, effective HVAC system.

Clearing up the terminology: Furnace filters, AC filters, and HVAC filters

Before we dive in, let’s address something that can be a little confusing: the terms furnace filter, AC filter, and HVAC filter. Essentially, they’re all talking about the same thing. Since the same filter works for both heating and cooling, the names are often used interchangeably depending on the season or context.

Whatever you call them, their role is the same: protecting your indoor air quality and keeping your HVAC system running smoothly.

Which HVAC filter is right for you? Understanding filter types

Picking the right air filter can feel tricky. Here’s what you should know about the most common options: 

Fiberglass

Fiberglass filters are made from thin glass strands, and they're the most common air filter type. This is a great option for most families and homes. 

Pleated

Pleated filters are generally made from folded cotton, polyester, or paper. Thanks to their increased surface area, pleated filters are great at capturing contaminants and allergens. 

HEPA

HEPA (High-Efficiency Particulate Air) filters trap more than 99.9% of particles at least 0.3 microns (smaller than the human eye can see) in size, making them especially ideal if your family has any health issues. 

Electrostatic

These washable, long-lasting filters use electromagnetism to capture airborne particles. These are perfect if you want to save money on filters. Just remember to clean them regularly! 

How to replace your furnace filter

Replacing a furnace filter is straightforward, but the process can vary depending on the type of system you have. Each system—from a return air duct, to an air handler cabinet, to a window AC unit—requires a slightly different approach. Below, we’ve outlined the steps for how to replace your furnace filter across systems to make the process simple and stress-free.

How to change an air filter in a return air duct

1. Unhook the latch and open the grille.
2. Remove dust from the grille. Wipe away dirt and debris with a microfiber cloth,
3. then use a brush or vacuum cleaner with a brush attachment to remove dust
4. from in between the slats.
5. Insert a new filter. Be sure to double-check its type and direction!
6. Close the grille and hook the latch.

How to replace an air filter in an air handler cabinet

1. Turn off power to your HVAC unit.
2. Unhook the latch and open the grille.
3. Remove dust from the grille. Wipe away dirt and debris with a microfiber cloth, then use a brush or vacuum cleaner with a brush attachment to remove dust from in between the slats.
4. Insert a new filter. Be sure to double-check its type and direction!
5. Close the grille and hook the latch.
6. Turn the power back on.

How to change an AC filter in a window AC unit

1. Turn off the unit and unplug it.
2. Remove the front cover.
3. Remove the filter.
4. Take the filter outside and shake it to remove as much dirt as possible.
5. Rinse the filter with soapy water, then rinse with clear water.
6. Scrub the filter in soapy water, then rinse.
7. Dry the filter with a microfiber cloth.
8. Allow the filter to air-dry.
9. Replace the filter.
10. Replace the front cover.
11. Plug the unit in and turn it on again.

FAQs for replacing air filters

Follow our tips for better home air quality while getting the most out of your filters:

How often should you change your HVAC filters?

Most filter manufacturers and HVAC companies recommend an air filter change every 90 days, but numerous variables can influence the correct frequency for you, your home, and your system. Important variables include:

• Pets: If you have cats or dogs that shed, their airborne hair could reduce the lifespan of your filters. 
• Health Issues: If you or a family member suffers from allergies or respiratory issues, a clean filter is essential for catching pollutants throughout your home. 
• Location: If you live in a dry, dusty, or polluted environment, a fresh filter can increase your indoor air quality. 
• Home Size: A large home requires a system that can pump large amounts of air—which increases the number of particles moving through your filter. 
• Filter Type: Most disposable filters can last 3-12 months under the best conditions, but washable filters can last longer—provided they’re cleaned regularly!

Which way does the air filter go?

Pay attention to filter direction! Most filters have an arrow printed on the frame showing which direction it should be placed to accommodate airflow. 

If the filter is placed the wrong way—so that the air is working against the filter—the system will have to work harder and use more energy. 

Book your HVAC tune-up

Regular filter replacement is a small job that brings big benefits—but it’s just one piece of the puzzle when it comes to keeping your HVAC system in top shape. Looking for more peace of mind when it comes to your furnace? Protect your HVAC Systems and other home appliances you use everyday with an AHS home warranty plan.

With an American Home Shield® home warranty, you’ll get additional benefits like HVAC tune-ups. That way, you can feel confident that your filters are functional and your systems are running smoothly, no matter the season.

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