Cabin Air Filter: The Drive's Garage Guide
The world may be on fire, but you don’t have to breathe it in.
- Cars 101
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The world is, quite literally, on fire. The wildfires of the American West are precursors to more fires each and every year. We must face that new normal. And even though we’ve made some strides to curb air pollution, C02 emissions still threaten our future. This type of blanketing intruder can be difficult to avoid, but your car’s interior can be a sanctuary from the fumes thanks to your cabin air filter.
While your car’s engine-feeding air filter screens the air entering the combustion cycle, a vehicle’s cabin air filter strains the air you breathe inside your ride. Think of cabin air filters as gas masks, keeping the pollution, smoke, and that bro-dozer’s disgusting coal-rolling out of your lungs and out of the hospital for acute asthma, bronchitis, and other respiratory diseases.
During this era of environmental instability, you might be wondering how cabin air filters work and if yours is good. You might also be curious about how long they last, what affects them, how much they filter out, and how to replace them. Well, fine reader of The Drive, have we got the guide for you! We’re going to discuss all of that, including a few questions you might not have thought about.
So, sit back, grab a canned air, and follow along as The Drive’s crack info team teaches you everything you ever wanted to know about cabin air filters.
What Is a Cabin Air Filter?
A cabin air filter is a flat, pleated, typically rectangular cartridge made of a framed combination of paper, mesh, and/or cotton that contains activated charcoal. As air is sucked into your car’s cabin, cabin air filters trap airborne contaminants and debris before it enters your personal space. They are usually housed behind your glovebox or at the base of your car’s windshield, underneath the hood.
What Does a Cabin Air Filter Actually Do?
Cabin air filters are designed to remove 99.995 percent of airborne contaminants down to 0.1-0.3 microns—a micron is 1/25,000th of an inch and is used to measure the size of particulates in the air. Essentially, they keep your lungs from breathing in pollution, wildfire/forest fire smoke, cow farts, your friend’s farts, skunks, and other things you don’t want to smell or let into your lungs.
How Long Do Cabin Air Filters Last?
Cabin air filters longevity depends on the manufacturer’s recommendations, along with a few external and internal factors that reduce the filter’s life. The typical cabin air filter’s lifespan typically ranges between 15,000-30,000 miles. That doesn’t include dealing with the following variables.
External and Internal Factors Affecting Cabin Air Filters
Life is full of variables that positively and negatively affect the health of you and everything else. Cabin air filters are no different. Here are a handful of external and internal variables that can affect your cabin air filter’s life and effectiveness.
What Internal Factors Affect Your Cabin Air Filter?
Cigarette, cigar, and marijuana (please don’t do that in your car) smoke can all affect the effectiveness of your cabin air filter. As you smoke more in the car, the filter becomes further clogged by your particular habits. Likewise, those who use hair spray or other beauty spray products can also impact the health of your cabin air filter.
Do Cabin Air Filters Filter Wildfire/Forest Fire Smoke?
Yes, they do. Cabin air filters are designed to filter out 98-99.995 percent of airborne particulates down to 0.1-0.3 microns. Wildfire/forest fire smoke ranges between 0.4-0.7 microns according to the EPA.
Can Your Window Seals Affect Your Car’s Air Quality?
They can! If your window seals have become cracked or are off their guides, outside air—and everything that goes along with it—can enter your cabin and affect your air quality. Maintaining your seals allows your HVAC system to properly recirculate the clean air without any extraneous pollutants entering your car.
How Does A/C Recirculation Work and Affect Your Cabin Air Filter?
Your car’s air conditioning recirculation setting is one of the most important tools in combating airborne pollutants. By selecting recirculate, you make your car as close to a closed-loop system, where the majority of outside pollutants never enter the car, as possible without having NASA-grade air scrubbers. This is especially handy with forest fires/wildfires where smoke is cut off from the cabin.
Signs of a Dirty Cabin Air Filter
The signs of a dirty cabin air filter are pretty easy to detect, that is unless you lack the sense of smell. Here are the most common ways to determine if your cabin air filter needs replacing.
You Smell Odors or the World Outside
The easiest sign of a dirty cabin air filter is the scent of something outside of the car, such as wildfire smoke, cow pastures, or skunks even when you have the HVAC system on recirculate.
You See Particulates or Smoke
Clearly there’s an issue if you see smoke or other particulates coming in through your car’s vents. This may also indicate your cabin air filter has a tear, rip, or break and needs to be replaced immediately.
Poor Air Flow
When a cabin air filter becomes clogged due to years of neglect, your car’s HVAC system may not be able to blow as vigorously as it did when new. It might feel as if you have an old Italian supercar, the A/C feeling like it was being blown through a straw by an asthmatic. Not good, Cotton.
You Can Hear The HVAC Struggling to Push Air Out
Likewise, you might hear the HVAC mechanism struggling to push the air through the car. It might sound louder than usual or as if something were blocking a vent.
What Happens When Your Cabin Air Filter is Dirty?
You get all the above signs of a dirty cabin air filter. And if you’re there, you’re either stuck breathing in your own eggy farts or, far worse, you’re breathing in the toxic pollution of a city’s emissions or the pea-soup-thick smoke from your residence’s wildfires.
Neither are good, as one doctor in San Francisco compares breathing in wildfire/forest fire smoke to “smoking eight cigarettes.”
How To Replace Your Cabin Air Filter
With all that information now at the forefront of your mind, especially for those experiencing wildfires and forest fires around the world, you’re probably wondering how to replace your cabin air filter. Stuff your worries in a sack, because The Drive’s info nerds have you covered. Let’s do this!
Cabin Air Filter Basics
Estimated Time Needed: Half-hour at most.
Skill Level: Beginner
Vehicle System: HVAC
Cabin Air Filter Safety
Working on your car can be dangerous and messy, so here’s exactly what you’ll need to ensure you don’t die, get maimed, or lose a finger and keep your jeans, shirt, and skin spotless—hopefully.
- When replacing an underhood cabin air filter, use a hood prop in case the struts don’t work anymore.
- Avoid sudden movements after removing the dirty filter. You don’t want to stir up and breathe in the dust.
Everything You Need To Replace a Cabin Air Filter
We’re not psychic, nor are we snooping through your toolbox or garage, so here’s exactly what you’ll need to get the job done.
- You, you’re the tool.
- Flathead screwdriver (maybe)
Organizing your tools and gear so everything is easily reachable will save precious minutes waiting for your handy-dandy child or four-legged helper to bring you the sandpaper or blowtorch. (You won't need a blowtorch for this job. Please don’t have your kid hand you a blowtorch—Ed.)
You’ll also need a flat workspace, such as a garage floor, driveway, or street parking. Check your local laws to make sure you’re not violating any codes when using the street because we aren’t getting your ride out of the slammer or paying any fines.
How To Replace a Cabin Air Filter
Now let’s get down to the nitty-gritty details on how to replace your cabin air filter.
Replacing In-Cabin Air Filter
- Remove the contents of your glove box, if you haven’t already.
- Remove the glove box door from its hinges. No tools are required, but a flathead screwdriver can sometimes help.
- Remove the old, stinky, smoke-saturated air filter from its slot.
- You can now replace it with a new cabin air filter.
- Reattach the glove box door and replace its contents. Don’t forget your insurance, registration, and that old takeout menu from Paul’s House of Deep Dish Pies you’re definitely saving for your next breakup (or simply next Monday).
Replacing an Underhood Cabin Air Filter
- Start the car and turn the windshield wipers on. Turn the car off when the windshield wipers are pointing toward the roof of the car.
- Pop the hood.
- Remove the windshield washer hose from the clips on the plastic cover near the base of the windshield.
- Pull away the hood weatherstripping.
- Remove the plastic cover (you may need a flathead screwdriver).
- Remove the cabin air filter.
- Replace with the new cabin air filter.
- Reinstall the plastic cover, hood weatherstripping, and windshield washer hose.
- Close the hood.
You’re done, congrats!
Get Help With Brake Issues From a Mechanic On JustAnswer
The Drive recognizes that while our guides are detailed and easily followed, a rusty bolt, an engine component not in the correct position, or oil leaking everywhere can derail a project. That’s why we’ve partnered with JustAnswer, which connects you to certified mechanics around the globe, to get you through even the toughest jobs.
So if you have a question or are stuck, click here and talk to a mechanic near you.
Pro Tips on Cabin Air Filters
The Drive’s editors have seen their fair shares of disgustingly dirty cabin air filters, plus, a couple of them live on the West Coast where wildfires and forest fires are common occurrences. With all that knowledge floating around our noggins, we let’s set a tap to release our pro tips when it comes to cabin air filters.
- If you live in an area where wildfires are prevalent, you’ll want to replace your cabin air filters every year. Yes, we know that’s a pain, but having breathable air is sorta a necessity for living a long life.
- Make sure your seals around your windows and door frames are good and not cracked. These are simple fixes and can save you from experiencing more fire or pollution inside your car.
FAQs About Cabin Air Filters
You’ve got questions, The Drive has answers!
Q. How Much Does It Cost to Replace Your Cabin Air Filter?
A. Most cabin air filters cost about $15-$30 depending on the level of filtration and your vehicle’s make and model. Some can cost more, and you’ll also pay more if you have a professional replace it.
Q. Do I Really Need to Replace My Cabin Air Filter?
A. Yes, you absolutely do. Without it, you’re breathing in the world’s pollution and filth. Do you want to breathe in the world’s grossness? We didn’t think so.
Q. How Often Should I Replace My Cabin Air Filter?
A. Most manufacturers say you should replace your cabin air filter every 15,000-30,000 miles. However, if you live in a place where forest fires/wildfires or pollution runs rampant, you’ll want to replace it yearly or even sooner.
Q. How Do You Filter Out Forest Fire Smoke?
A. By replacing your cabin air filter and turning your HVAC system onto “Recirculate.” That’s the little button on your dash that looks like a look with an arrow.
Q. What Does Tesla’s Bioweapon Defense Mode Do?
A. According to Tesla, the brand’s Bioweapon Defense Mode was “developed a HEPA filtration system capable of stripping the outside air of pollen, bacteria, and pollution before they enter the cabin and systematically scrubbing the air inside the cabin to eliminate any trace of these particles. The end result is a filtration system hundreds of times more efficient than standard automotive filters, capable of providing the driver and her passengers with the best possible cabin air quality no matter what is happening in the environment around them.”
Essentially, it’s a cabin air filter on steroids.
Q. How Long Does Tesla’s HEPA Filter Last?
A. Tesla claims it will last up to three years.
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