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  • Writer's pictureChad E.

DIY Guide: How to Replace Your Air Filter


The filter in your furnace is an important piece of your HVAC system. It serves as a barrier, removing dust and allergens from being circulated throughout the air in your home. Indoor air health problems are an issue in 8 out 10 homes, and indoor air can be up to 100 times more polluted than outside air, according to studies by the U.S. Environmental Protection Agency.

A dirty filter allows for dust, dirt, pet dander and mold to continue circulating through your home. As a result, your family’s health may suffer, especially those who are prone to allergies and asthma. A clean filter will also reduce the amount of dust in your home.

Filters also don’t just improve the quality of air; they also protect your HVAC system from damage. A dirty filter makes your system work harder to move warm air efficiently throughout your home. Dirt can also accumulate on coils resulting in further restricting airflow. When your system has to work harder, parts may wear out quicker and need to be replaced sooner. The life of a HVAC system can also be reduced as well requiring more energy to operate, thus increasing your heating costs. Replacing a dirty filter can lower your furnace’s energy need by as much as 15 percent.

Know the System Specs

Before you can perform an HVAC system filter change, you need to know exactly what size and type of replacement filter you’ll need. If your system is still under warranty, make sure you use the exact type of filter your owner’s manual recommends.

If you don’t use the recommended filter, your warranty may be voided or you might not be able to make a claim if you run into problems later. For those who don’t currently have a system under warranty, you still need to know the exact size of the filter.

Once you know the size of the filter, you’ll want to look into the various styles available. As a general rule of thumb, you should make an HVAC filter change every month.

Some filters are available in three or even six-month designs that can remain in use for a longer period of time. Write down the date you change the filter so you can keep track of when it’s time to replace it later on.

In addition to the size, consider the various indoor air quality issues you have. For example, if you or someone in your household has allergies, consider a special filter designed to help capture excess pollen, dust, and dander.

A HEPA filter is a good choice for anyone coping with indoor allergies. Regardless of the filter style you choose, it’s essential that it’s the exact type required for your unit.

Make a note of the size of the replacement filter so it will be much easier to buy new ones going forward. Most filters have the size listed on the side for quick access.

Remove the Old Filter

The type of HVAC system you have will determine where your current filter is located. For some central air conditioning systems, the filter is located under a grate in the ceiling or near the floorboards.

Look for the return register, and then adjust the closing mechanism to open the panel. These are usually two small pieces of metal that you can easily turn outward to release the panel.

For other HVAC systems, the filter is located inside the inside unit behind a panel. You should be able to see ductwork coming into your internal unit. This ductwork will lead air coming in, and then another run of ductwork will lead air out of your home.

The filter should be located between the ductwork that brings the air in and the actual furnace itself. Other models might use a small panel with a handle that lifts the panel off.

You might also locate your filter on the bottom of your HVAC system unit. In this case, you’ll likely need to remove the front access panel first.

Once you’ve found the location of your air filter, carefully remove the panel. If it’s attached using screws, be sure to keep them in a safe place so you can easily replace the panel when you’re done.

If you are especially sensitive to dust and pollen, use a mask and gloves to remove the old air filter. Dispose of the filter by placing it a garbage bag. Then, seal the bag and throw it in the trash outside.

if it appears that there’s a lot of excess buildup inside your HVAC unit, now is a good time to go ahead and vacuum that out before you replace the filter.

HVAC Filter Change: Replace or Clean

In many instances, you’ll replace your system filter with a new, disposable version. These filters usually have a cardboard frame, and you can find them at most home improvement stores.

When you replace the filter, make sure that you insert it in the correct direction. The filter should have an arrow or several arrows printed on the side.

The purpose of these arrows is to show you which direction to place the filter so that the air is flowing out of it in the correct direction. Simply place the filter inside the designated area, and securely close the panel door.

Always make sure that the filter fits snugly and there are no gaps around the frame. This will keep it in place, and it’ll help to ensure that all dirt, debris, and dust is getting filters out before the air flows into your home.

You might have a “permanent” HVAC filter. These filters are able to be cleaned, and they’re usually made with a sturdy fiberglass frame. The cost for a permanent filter might be more upfront, but it can save you money in the long run.

If you have a permanent filter, remove it following the same steps listed above. Then, rinse the filter in the sink or tub with clean water. Gently scrub the filter with a soft brush and mild detergent.

Continue rinsing and lightly scrubbing until all the excess grime is removed. It’s very important that you allow your permanent filter to dry completely before replacing it inside the unit.

If there is a little bit of water, don’t fret. The flow of air from your HVAC system should dry the remaining moisture pretty quickly.

Permanent air filters are a good alternative if you prefer something that’s environmentally friendly and long-lasting. Keep in mind that these filters still need to be cleaned on a monthly basis, just as you would replace a disposable one.

Whichever type of air filter you use, always wipe down the panel or register when you’re done. Clean this area of excess dust and buildup, which will allow for better airflow.

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