Best Cabin Air Filter - Car Talk

Car Talk's Top Recommendations Explained

The following are recommendations based on interviews with ASE-certified mechanics.

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Car Talk’s experts have differing views on cabin filters, and for good reason. Junior Damato is a professional mechanic who only uses the very best parts that can be found for his and his customers' vehicles. Junior favors the best filter you can buy, whether a full-featured aftermarket filter or an OEM one. John Paul also leans towards the best filter he can find. I am the voice of opposition here. I buy the cheapo filters from the internet and change them often. I believe a clean, cheap filter is better than a perfect one at the end of its life. You will need to pick your own path! Use the force, if you must.

Here is a list of some filters that are affordable and some that are pricey. None of them are bad; they just offer varying features. You will see my preference for cheap filters reflected in our picks.

What are cabin air filters, and what do they do?

Cabin filters help to remove dust, pollen, and other particulates from the air that enters your vehicle. They work like any other air filter. As air passes through the media, the contaminants are blocked or stuck to the filter. They are not high-tech parts, so buying one from your dealer’s parts counter is unnecessary.

In most cases, you can easily install a cabin air filter yourself. It can be as easy as following a video you can find online. The air filter is often located behind your glove box.

In an earlier version of this article, we overstated the simplicity of the process in some vehicles, as well as the filter's placement. Many thanks to the Facebook followers who set us straight, including Phil P. who explained, “Our 18 Yukon has no less than 6 Torx screws to get to the filter.”

And, Stu C, who wrote, “One of my cars is a Mazda MX-5. It has a cabin air filter, but no glove box. So instead of a five-minute drop-the-glove-box-swap-the-filter, I would have to remove about half the dash. Remove the kick panel and the dash fascia, drop ducting, unplug several wiring connectors. The how-to video is half an hour long.”

Oof. Reader, we hope you don’t have to jump through 57 hoops to change your filter. However deeply buried or not, Car Talk recommends changing your filter at least once a year. The best time to do so is the week after the spring pollen subsides.

What to consider when buying a cabin air filter

In this story, as our example, we used a cabin air filter for the most popular vehicle in America, the Toyota RAV4. When you shop for a filter, always check to ensure it matches your vehicle's year, make, model, and trim. Trim is generally less critical. Most filters sold will fit a certain range of models, but some are unique to the vehicle.

Air filters basically offer three features. The first is activated carbon. The ideal is that it will help reduce odor and contaminants in the form of gas. We cannot prove that activated carbon does anything. The second feature is a particle blocking spec known as “HEPA.” It stands for high-efficiency particulate attenuation. Sounds fancy. However, there are many other specs to go along with HEPA, and these filters sort of sidestep that fact. If you want the best particle blocking, buy a HEPA filter, but don’t blame us if the flow rate is reduced. The third feature is price. Most aftermarket filters cost roughly a quarter of an OEM filter, and they get great reviews from owners. So why buy OEM? Expert mechanic Junior Damato says that based on his experience, the OEM filters are more dense and likely remove more particulates than the cheap ones. No single brand dominates the aftermarket filter industry, so our advice is to let price and reviews be your guide.

What costs are associated with buying cabin air filters?

Cabin air filters purchased online from Amazon or other retailers will be less expensive than those you buy directly from your local dealership’s parts counter. We shopped around for examples of what a cabin air filter element costs for America’s top-selling model. Here is what we found:

• OEM - Toyota RAV4 Official Toyota Part (-YZZ93) = $36.99
• High-feature filter - $24
• Best value = $8

As you can see, you can buy about four aftermarket filters for the cost of one OEM filter. You can also load up on features (that may or may not have any real value) and still pay less than OEM.

Whatever you do, don’t let the dealer charge you to install a cabin air filter. Honestly, this is a task that almost anyone can accomplish in about two minutes, unless you’re Stu C, who has to work for it. Either way, realistically, you can’t cause any harm to the vehicle. If you let a dealer charge you for a filter, expect to pay between $50 and $100 total.

Can I DIY the installation of a cabin air filter?

Most vehicle owners can change their own cabin filter. There are endless videos on YouTube showing you how to do it step by step. In many cars, the first step is emptying the glove box, which offers a great opportunity to hide any evidence of junk food! You can also check that your registration and insurance info are current and handy. Last, if you have a flashlight in there, change out the batteries.

In most cases, changing a cabin filter is an easy one on a scale of one to five. You really can’t mess it up, so go for it! Chances are good that minimal tools are needed. The car will even run just fine without one.

Ray says, “If you can hang a picture, you can change a cabin air filter.”

We test HVAC filters in an isolated room with its own air circulation duct, cut off from the rest of our building’s heating, cooling, and ventilation systems. The temperature and humidity are controlled, and we clean the air in the room prior to each test. Then we inject two substances into the room: a mixture of dust in various particle sizes, and smoke from standardized research cigarettes.

Once the air quality gets as bad as we need it to be for our test, we turn on the air circulation in the room and use a particle analyzer to measure how quickly the filter reduces the particle count. We also monitor how much each filter restricts airflow, using a differential pressure transducer installed across the air filter.

Our top-rated models are fantastic at capturing pollutants while allowing enough air to flow through to keep your heating and cooling system running optimally. The worst models capture very little pollution or significantly restrict airflow—or sometimes both. 

We also calculate the annual costs of replacement filters, assuming that your system needs only a single filter, and based on the manufacturer’s recommendation for when to change them. Keep in mind that prices may vary by retailer and that it may be cheaper if you buy filters in bulk.

The industry standard for an HVAC filter’s performance is measured according to the MERV scale (Minimum Efficiency Reporting Value—rolls off the tongue!), from MERV 1 through MERV 16. Some sources have claimed that the scale reaches MERV 20, but the testing standard has been updated to clarify that MERV 16 is the maximum. 

At the low end of the scale, the filters are made from fiberglass or mesh, and can capture large particles like hair, fibers from clothes and carpets, and some pollen. Disposable fiberglass filters can cost just $2 each.

With competitive price and timely delivery, Purefine sincerely hope to be your supplier and partner.

As the rating increases, the filters can progressively capture smaller particles—and they tend to cost more. Around MERV 8, filter designs typically switch to pleated media (nonwoven material made of things like fiberglass paper, polyester, and plastic), and can reliably capture pollen, mold spores, and many types of household dust. 

At MERV 13—the highest rating you’ll find for most of the popular residential HVAC filter sizes—you can count on the filter to stop bacteria, smoke, and other microscopic particles. These filters can cost $40 or more.

Most home improvement stores sell HVAC filters ranging from MERV 1 to MERV 13, though CR has tested models as high as MERV 16. But some filters with midrange and higher MERV ratings might cause problems in residential HVAC systems. (More on that later.)

Some filter brands and retailers use alternative scales, like Home Depot’s Air Filter Performance Rating (FPR) system or MPR (on 3M Filtrete air filters). But the MERV rating will also be printed on the packaging or in the online product descriptions. 

Many manufacturers also say their HVAC filters are “allergen” filters (or something similar). But these are usually just filters with a rating of at least MERV 11, the rating where filters begin to catch the majority of particles that are the size of common allergens. There’s nothing uniquely anti-allergenic about these filters, and other filters with the same MERV rating should capture allergens just as well.

This typically means first finding your existing filter (or filters). HVAC filters are often located in a slot next to your furnace or air handler. But some HVAC systems have filters inside the return air ducts scattered in multiple rooms throughout your home. (Those are the grates that suck air back in, rather than blowing air out.) 

Once you’ve found each filter, make sure it’s the proper size, measured in inches of length, width, and depth (or thickness). If there are gaps around the sides or it doesn’t line up with any gaskets, it might be the wrong size. If your existing filters are a perfect fit, write down (or take a picture of) the size printed on the filter frame. When in doubt, check for the proper filter dimensions in your equipment’s owner’s manual, or get in touch with the manufacturer. 

You’ll often find an exact fit in stock at a hardware store, but sometimes you’ll need to order the correct filter size online. (And if you’re reading this from the filter aisle at the hardware store, don’t bother trying to guess the size—there are at least a dozen common dimensions, and you’re likely to choose incorrectly.) 

Take particular note of the thickness because it will affect the next decision you have to make (in step 2). Most residential HVAC filters are 1 inch thick, but 4-inch filters are becoming common, too.

Any pleated HVAC filter can improve your home’s indoor air quality by snagging dust, pollen, and other small particles—sort of like a quieter, more passive vacuum cleaner. 

But a filter that’s too dense for your setup can make it harder to heat and cool your home effectively and efficiently. It might also damage your furnace, AC, or heat pump over time as parts overheat or freeze solid.

A filter that’s unnecessarily loose isn’t great, either. It’s a missed opportunity to breathe cleaner air—and it also could damage your HVAC equipment over time as gunk accumulates on the blower and coils.

So the right amount of filtration is about finding the sweet spot: a filter that allows ample airflow through your ducts while capturing as much debris as possible. 

Remember how we said to take particular note of your filter’s thickness, which will usually be 1 inch or 4 inches? This is where that detail becomes important, because it might affect how much filtration your system can handle.

1 inch thick: These can be tricky to shop for, according to many HVAC professionals, because 1-inch filters with high MERV ratings are especially likely to be too restrictive for some HVAC systems. 

Nevertheless, CR has tested several 1-inch, high-MERV filters (MERV 11 and up) that earn a very good rating on our airflow test (that’s like scoring a 4 on a scale of 1 to 5). They tend to be pretty expensive, though. Models that earn the highest rating on our airflow test also tend to have lower MERV ratings, and cost less, though they don’t perform as well on our particle-capture tests. CR members can see the top performers in our full air filter ratings. 

If you want to be certain about how much airflow your HVAC system requires to function properly, you’ll need to measure the static pressure. (Basically, that’s the resistance to airflow in your ducts, based on a handful of factors.)

A qualified technician with basic tools of the trade can take the measurement in a couple of minutes—for example, when they’re already at your home performing a system tuneup—and advise you on how to pick filters that will work well with your equipment.

If you can’t take a measurement, experts sometimes recommend sticking with a MERV 8 pleated filter as a safe-harbor option. Filters with this rating allow plenty of airflow, so they’ll be safe for most systems. They also don’t cost much, and they catch a lot more debris than basic fiberglass filters can.

4 inches thick (or greater): If you already have a filter cabinet that can handle a filter of this thickness, you can feel confident that even a high-MERV filter will work well with your HVAC system.

The secret is that they can capture tons of debris while using relatively porous filter material, thanks to the huge surface area that dirty air has to pass over—about four times as much filter media as on a 1-inch filter. A MERV 13 is a great choice at this size, delivering excellent air quality for a reasonable price. 

If you currently have 1-inch filters, you could consider upgrading your system to accommodate 4-inch filters. Your HVAC pro would install a small cabinet next to your furnace or air handler (on the air-intake side) to hold the thicker filter. The work should cost only hundreds (not thousands) of dollars.

Contact us to discuss your requirements of cabin air filter manufacturers. Our experienced sales team can help you identify the options that best suit your needs.