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When Is It Time To Replace My Cabin Air Filter?

Situated within a vehicle’s ventilation system, cabin air filters trap dust, pollen, smog, mold spores, and other pollutants. We discuss how they work, and how often replacement is needed.

What Does A Cabin Air Filter Do?

If you own a car or truck built since the early 1990s, the HVAC (heating, venting & air conditioning) system which provides heated and cooled air to the vehicle’s interior is likely equipped with a lightweight, removable cabin air filter. As its name suggests, the purpose of this filter is to help clean the air you breathe by filtering out and trapping dust, pollen, smog, mold spores, and other types of airborne pollutants.

After cabin air filters were introduced on high-end luxury cars, automakers realized they were very effective at cleaning the air and making life easier for passengers with asthma, allergies, and other respiratory conditions. Feedback from customers regarding improved air quality was so positive that cabin air filters became a selling point in their own right. Since amending existing HVAC systems to accommodate such filters didn’t require much in the way of redesign, it wasn’t long before this feature became standard equipment on vehicles of all price points – even entry-level economy cars.

New / Worn-Out Cabin Air Filters

Should you decide to check your owner’s manual on the subject of replacement, you may see it states to replace the cabin air filter every 15,000 miles. Or 20,000 miles. Or 22,500 miles. Or maybe even 30,000 miles depending on the vehicle manufacturer.

Depending on the service facility you use, you may be advised to replace your cabin air filter more or less often than that as a matter of maintenance, while other shops will forget about this item entirely. A dealership service department may inspect it during a routine vehicle checkover and tell you a new one is required on the spot, regardless of how recently the old one was installed.

Our Personal Experiences On The Subject

If all of these conflicting opinions leave you scratching your head about just how often you really need to replace your cabin air filter, we understand. A little while back, this topic was the very subject of a discussion among CARiD office staffers. While some opinions varied widely, most of the group was divided into “replace at 15k” versus “replace at 30k” camps. To try to find an answer to this question, a number of us replaced our cabin air filters and started out with new ones at the same time.

What we found, living in a densely populated Northeast region that sees all four seasons, was that after trudging 15,000 miles through springtime pollen, summer air conditioning use, fall foliage, and full-blast winter heating/defrosting, our cabin air filters were all dirty at that point.

Also trapped in some of the filters were small twigs, leaf debris, and acorn bits. These kind of items can get in there, since air ducts leading directly to the filter draw outside air from under the windshield or cowl. Gratework over the fresh air intake varied depending on the vehicle – some had big slats which allowed lots of debris to fall through, while others blocked more.

We’re accustomed to our four-season climate, yet we also recognize that not every part of the country endures such climatic changes. We do not automatically recommend that everyone needs to replace their cabin air filter at 15,000 miles, as that will depend in part on driving conditions in your part of the country.

However, you can check the condition of it at 15,000 miles. This is easy to do because these filters are usually easy to slide in and out – accessed from under the passenger side of the dash or by removing a cover panel on the back of the firewall in the back of your engine bay.

Various Factors Can Affect Cabin Air Filter Lifespan

If you live in a dry climate that’s free of pollen and falling leaves, your filter may still be fine at 15,000 miles and have a lot of life left in it. At the same time, it’s also a fact that desert climates with fine layer of silt in the air can clog cabin air filters equally well. Inspect the filter closely, as such light-colored dust may be easy to overlook at first.

If you drive in a smog-laden area or on spend significant time on crowded freeways with loads of trucks, your filter may blacken visibly over time with deposits. If you live in a wooded area and drive amongst lots of trees (especially oaks), pollen will be the biggest contributor to clogged filters.

While cabin air filters do help with odors, excessively humid conditions in extreme cases can actually create dampness at the cabin air filter and impact its ability to control smells.

Effects Of A Clogged Cabin Air Filter

Picture the lint-catching screen in your dryer, and how clogged it can get doing its job under normal circumstances. Once airflow is reduced on a clogged screen, efficiency is lost and clothes take much longer to dry. Similarly, a cabin air filter suffers the same fate as the dryer’s lint-catching screen.

Dust and pollen that sit on the surface of a cabin air filter can begin to grow mold, fungi, and other bacteria in humid environments. If you notice a moldy smell when the A/C is turned on, it may be past time to replace the filter. Doing so is a prevention measure against further mold growth.

As air does manage to find a way past a clogged air filter surface, it will be through a smaller and smaller portion of the filter. So what does make it through won’t be as well filtered overall.

Opportune Times To Replace A Cabin Air Filter

We’ve already discussed a) manufacturer’s recommendations; b) our own experiences in our own vehicles; and c) outside factors which can shorten this filter’s life. As a general rule, when should you think about replacing the filter?

Since most such filters are in the passenger compartment, they are not in proximity to other frequent-service items. We prefer the “time” interval over the “mileage” interval, and once a year for many of us is an ideal compromise. One good way to think about it is as part of the vehicle’s spring service ritual. Once winter is over, you may be turning on your A/C for the first time in a while. Perhaps you are removing winter tires and checking all fluid levels. Add the “check and change the cabin air filter” to your springtime checklist, and you’ll be assured of having a fresh filter to maximize the cleanliness of the car’s or truck’s interior air.

Inspecting Or Changing A Cabin Air Filter Is Easy

In most cases, all you really need to inspect a cabin air filter (or swap in a new one) is some basic hand tools and about 10 minutes. These filters are usually rectangular in shape, and relatively flat in order to slot easily into a narrow housing. Below, we’ll examine the two common locations where you’ll find cabin air filters, and we’ll show you how to access them. They’re either under the passenger side of the dash, or behind a cover panel in your engine bay below the windshield somewhere.

Some vehicles may require temporary removal of the glovebox assembly in order to access the filter under the dash. Generally, removing a glovebox assembly is not difficult – but we have left instructions on this out because removal methods can vary greatly from vehicle to vehicle.

Under The Dash

Cabin Air Filter Mounted Beneath Dashboard
Many vehicles feature a cover panel which must first be removed by taking out several screws or bolts.

For cabin air filters mounted beneath the dash, take a look underneath in this general area. Many vehicles feature a cover panel which must first be removed to access the filter housing. If so, look for bolts or screws holding it on, then take them out.

When you can see the guts of things underneath the dash, look for a rectangular cover plate that’s part of the cabin air filter housing. The cover plate may be positioned from front-to-rear, or from side-to-side depending on the vehicle. Once you remove any nuts or bolts holding the cover plate in place, it may open on a hinge or pop loose completely.

One Screw Rectangular Cover Plate As Part Of Cabin Air Filter Housing
The housing which actually holds your filter has its own cover plate that needs to be unbolted. On this vehicle, only one screw needs removal.
Rectangular Cabin Air Filter
Once the cover plate is out of the way, you can access the rectangular cabin air filter. To remove, grab it and pull down.

Once the cover plate is out of the way, you should be able to see the bottom edge of the cabin air filter. As you grab onto it and pull down with slight pressure, some wiggling may be necessary to free it completely.

As a best-practice, make note of the filter’s orientation before completely removing it. Some filters must be installed facing in a particular direction.

Under The Hood

Cabin Air Filter Mounted Under Hood Close To Dashboard
Cabin air filters mounted under the hood are usually positioned close to the dashboard. Once a cover panel is unbolted, it can be removed.

Vehicles with cabin air filters mounted under the hood usually position them as close to the dashboard as possible. Typically, there’s a cover panel somewhere by the base of the windshield held in place with hold-down screws. Simply remove them, flip up the cover panel, then slide out the cabin air filter. The suggestion to note the filter’s orientation is applicable here too.

Cabin Air Filter Under Flipped Up Cover Panel
After removing or flipping up the cover panel, the cabin air filter can be accessed.

Cabin Air Filters We Offer

We carry the AC Delco GM Original Equipment Cabin Air Filter (GM and other makes), Denso Cabin Air Filter, Bosch Cabin Air Filter, Mahle Cabin Air Filter, Mopar Cabin Air Filter (Chrysler OEM), Motorcraft Cabin Air Filter (Ford OEM), and Genuine Cabin Air Filter just to name a few.

The K&N Cabin Air Filter is somewhat unique in that, like their engine air filters, they are designed to be washed and reused.

"Particulate" Filters vs. "Carbon" Filters

We sell both particulate cabin air filters and carbon cabin air filters, and many of the ones listed above can be selected in either style once you get to the Product Options screen. Both are constructed in the same general fashion, and have the same overall vehicle-specific fit dimensions. Particulate filters are usually fitted as OEM equipment, and do a great job of trapping and holding dust, pollen, and other floating contaminants.

Standard Particulate Cabin Air Filter
A standard "particulate" cabin air filter.

Carbon filters also trap these things, but add a superior ability to trap noxious exhaust fumes and other things that cause unpleasant odors. This is because the charcoal in the filters is heat-treated with certain chemicals that hold the odor-causing contaminants on the surface of the charcoal treated filter. So if you live in an area where odors are a particular concern, or if you find that your vehicle is more susceptible to HVAC smells, a charcoal filter may be worth the extra expense.

Carbon Cabin Air Filter
A "carbon" cabin air filter.

It's really common sense - breathing cleaner air helps us feel better. When you think of how much time you spend in your vehicle, a clean and well-working cabin air filter can really make a difference. In this day and age, when so many of us are more focused on taking care of ourselves by eating better and living overall healthier lifestyles, it makes sense to also do our part to ensure that the cabin air in our vehicles is as clean as can be.

Cabin Air Filters Gallery

In addition to the cabin air filters themselves, we also offer related parts such cases and covers that serve to house the filter. If you should find yourself with any inquiries on what we sell while you're making your selection, give us a call - our knowledgeable specialists are here 7 days a week!

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