Best AC Filters of 2021 – Complete Guide

An air filter is one of your HVAC system's simplest components, and for that reason, it is often overlooked. When sweltering summer temperatures seem to have your HVAC struggling to keep up, or if your system is not providing the cozy warmth you are seeking indoors in the winter months, do not overlook the obvious.

Before you call in the repairman as yourself, “when is the last time I changed the filter?” You would be surprised how often a poorly performing system is simply due to a dirty filter.

Comparison of the Best AC Filters

  • Picks up 99% of airborne contaminants
  • Lasts from 30-90 days
  • Highlighted by a hypoallergenic electro-static material
View Latest Price ?
  • Filters small and large airborne pollutants
  • It is asthma and allergy friendly
  • Lasts up to 3 months
View Latest Price ?
  • Best for the Money
  • Attracts more than 90% airborne pollutants
  • Efficient at temperatures up to 200 degrees Celsius
View Latest Price ?
  • Best Air Conditioner Filter for Allergies
  • Merv-13 filter removes spores, mold, bacteria, dust, dander
  • Reduces air that bypasses the filter
View Latest Price ?
  • Best 20x30x1 AC Filter
  • Traps dust, mites, pollen
  • Purifies air with merv-5 filter
View Latest Price ?
  • Best AC Filter for Airflow
  • Made out of washable fiberglass
  • Coming in a pack of 12
View Latest Price ?
  • Best Washable Air Conditioner Filter
  • Holds airborne particles with natural static charge
  • Durable with a rust-proof aluminum frame
View Latest Price ?

What is an AC Filter, and How Does it Work? 

An AC filter acts as a defense system between you and all of the things you do NOT want circulating in the air in your home: think dirt, dust, and allergens. For people who suffer from seasonal allergies, the last thing you might want is an AC system pumping pollen into your living room.

The filter is not only protecting you—but it is also protecting your HVAC system. By reducing the amount of dirt and debris that can clog your air conditioning, you ensure that the system can run properly and last longer. Even the most expensive air filters are a minor expense when you consider the costs of replacing an entire HVAC system.

What Size Air Filter Do I Need For My Air Conditioner? 

Because air conditioning systems themselves come in different sizes, built to cool everything from a small apartment to large office buildings, the filters they use come in a wide variety of sizes. This can be especially confusing for homeowners.

FilterBuy Pleated AC Filter

If you make that first trip to your local home improvement store to look for a new filter without checking the size first, you will inevitably have to turn around and go right back home once you see the selection.

The most common sizes are listed below, which you should generally have no trouble finding or ordering online. The easiest way to determine the size you need is to pull out your existing filter, or you can also check the owner’s manual for your AC system.

Standard Air Filter Sizes

10 x 20

14 x 20

16 x 24

18 x 30

12 x 12

14 x 24

16 x 25

20 x 20

12 x 20

Why Did These AC Filters Make Our List? 

When reviewing the best AC filters available, we considered several factors, including price, performance, and durability.

Additionally, we considered the needs of allergy sufferers, whose filters should go the extra mile to remove allergens such as dust and pollen from the air.

Finally, we were happy to include some Made in the USA products as well as those designed with eco-friendly materials.

Lennox X6675

Review of the Best AC Filters 

If you are in the market for air filters--whether you have a brand-new AC system and you need to stock up or if you are replacing dirty ones—we have a roundup of the best filters for every need.

Best Overall:
Nordic Pure MERV 12

Nordic Pure 16x25x1 (15 1/2 x 24 1/2 x 3/4) Pleated MERV 12 Air Filters 6 Pack


  • Available in packs of 2, 3, 6, or 12
  • Made in the USA with high-quality materials
  • Material prevents the growth of mold or bacteria
  • Frames made of recycled beverage board paper for eco-conscious consumers
  • Filters out pet dander and effectively removes allergens such as pollen and dust mites


  • Filter density can be hard on some systems
  • Some buyers considered the product flimsy compared to some others

What Recent Buyers Report

Overall, buyers are satisfied that the Nordic Pure filter gets the job done without being ridiculously expensive. While occasionally some consumers find them “flimsy,” this is a good, standard disposable filter you can rely on to eliminate dust and other allergens that may be circulating in your home.

Why it Stands Out to Us

We like that the Nordic Pure is available in different packs and has some eco-friendly components in its design. The frame made of recycled beverage board is a plus, and we also find that this filter effectively removes all the things we do not want circulating in the air.

Bottom Line

For an inexpensive yet effective solution to your AC filtering needs, the Nordic Pure is our number one pick.

Filtrete Ultrafine MPR 2800

Filtrete 20x30x1 Air Filter, MPR 2800, MERV 14, Healthy Living Ultrafine Particle Reduction 3-Month Pleated 1-Inch Air Filters, 2 Filters


  • Subscribe and save option
  • Backed by the 3M name, a leader in technology
  • Filtrete Smart App with handy replacement reminders
  • Can be used for up to three months before replacement is needed
  • Consistently outperforms fiberglass, washable, and non-electrostatic filters


  • Airflow affected by pleats
  • Somewhat expensive compared to other options

What Recent Buyers Report

While some buyers think the pleats in these filters are not conducive to the best airflow, most consumers are happy with a Filtrete Ultrafine purchase. This is a trusted name from 3M, a company that many consumers are familiar with thanks to its many products that make our lives easier, safer, and healthier.

Why it Stands Out to Us

The Filtrete Ultrafine lives up to its name, removing even the finest particles circulating in the air. Microscopic particles such as smoke, bacteria, and debris are captured by this high-performing filter, as well as common allergens such as dust and pollen.

Bottom Line

The Filtrete is worth the price based on its performance, even if it’s on the higher end for some consumers.

Best for the Money:
FilterBuy Pleated AC Filter

Filterbuy 20x20x1 Air Filter MERV 8 Dust Defense (4-Pack), Pleated HVAC AC Furnace Air Filters Replacement (Actual Size: 19.50 x 19.50 x 0.75 Inches)


  • Budget-friendly price points
  • Traps 90% of airborne particles
  • High-quality filter frames with synthetic media
  • Designed to last for up to 3 months before replacement needed
  • Manufactured in the USA with components all 100% American-made


  • Sizing issues with some smaller than listed
  • Some complaints regarding density and airflow

What Recent Buyers Report

Nothing makes a consumer happier than a bargain product that works, and FilterBuy does just that. This is a no-nonsense, basic air filter that gets the job done at a good price.

Why it Stands Out to Us

The FilterBuy comes in every size imaginable to fit AC systems, large and small. And no matter what size you need, this filter will deliver when it comes to performance. We appreciate that this is a truly All-American made product, and the fact that it traps 90% of the airborne particles in your home will mean cleaner living and better overall air comfort.

Bottom Line

For the average homeowner who wants clean air but does not want to break the bank to get it, this filter is a solid choice.

Best Air Conditioner Filter for Allergies:
Aprilaire 413 Healthy Home

AprilAire 413 Replacement Filter for AprilAire Whole House Air Purifiers - MERV 13, Healthy Home Allergy, 16x25x4 Air Filter (Pack of 2)


  • Comes in packs of 1, 2, 4, or 8
  • Easy to install with unique interlock rail system
  • Reduced time vacuuming and dusting for homeowners
  • Aprilaire self-seal technology minimizes air bypassing the filter
  • Removes airborne allergens such as dust, pollen, mold, and pet dander


  • May require an adapter for the correct fit
  • Higher price point than basic disposable filters

What Recent Buyers Report

Allergy sufferers will often do anything to seek relief and minimize their symptoms--and if there is a filter that means reduced allergies, they will choose it regardless of price.  Customers report an almost immediate difference in allergy symptoms once this filter is installed.

Why it Stands Out to Us

If a filter can reduce a nagging cough or mean relief for itchy, watery eyes, it’s an easy win in our book. We love the reliable performance of the Aprilaire filter and the fact that it is designed and manufactured in the USA.

The self-seal technology is impressive, and it drives the performance of this filter right past its competitors.

Bottom Line

If you want to spend less time reaching for a tissue every day and want to sleep like a baby instead of spending your nights coughing, this filter is the one for you. The Aprilaire is a must-have filter for homeowners with everything from seasonal to severe, year-round allergies.

Best 20x30x1 AC Filter:
Filtrete MPR 300

Filtrete 20x30x1 AC Furnace Air Filter, MERV 5, MPR 300, Capture Unwanted Particles, 3-Month Pleated 1-Inch Electrostatic Air Cleaning Filter, 6-Pack (Actual Size19.81x29.81x0.81 in)


  • Can last up to three months
  • Metal-free support system and easy to install
  • Affordable price point without sacrificing quality
  • Removes pet dander, pollen, smoke, and dust particles
  • Trusted manufacturer with a solid reputation for quality products


  • May need to be changed more often than other filters
  • May not be effective enough for those with severe allergies

What Recent Buyers Report

Consumers who need a 20 x 30 x 1 filter often give this one from Filtrete high marks, both for its performance and price point. This is a well-constructed, basic filter for those with basic needs.

Why it Stands Out to Us

We are fans of Filtrete products as this is the second one in our roundup; for quality at an affordable price, they are among the very best choices in AC filters.

We have seen instances where 60 to 90 days is a reasonable life span for this filter, which is another plus. However, we think consumers should be prepared to change them in 30 days if needed.

Bottom Line

Filtrete consistently delivers a quality filter, and this is our favorite for 20 x 30 x 1 size AC filters. If that is the size you need, this is the filter you want.

Best AC Filter for Airflow:
Flanders EZ Flow

AAF Flanders EZ Flow 20 in. H x 20 in. W x 1 in. D Fiberglass 4 MERV Air Filter (Pack of 12)


  • Manufacturer a leader in air filtration systems
  • Flow arrows on the packaging for easy installation
  • Available in 1” and 2” models and all standard sizes
  • The 12-pack quantity is convenient (a year’s supply)
  • Both economically and environmentally friendly design


  • Some consumers describe it as flimsy
  • Some consumers prefer a higher Merv rating

What Recent Buyers Report

An affordable choice for those who change air filters monthly, the EZ Flow filters from Flanders are highly rated among consumers for both performance and price.

Why it Stands Out to Us

Flanders is a leading name in air filtration, and we like this filter’s performance when it comes to the quality of airflow; and we are delighted that the price tag is reasonable, too.

These need to be changed monthly for the best performance, and they do a satisfactory job of collecting household dust and debris. These are not intended for serious allergy sufferers (see our suggestion for that filter below), but they are still a solid choice for most users.

Bottom Line

This basic air filter does the job of removing contaminants to keep clean air flowing; we think the EZ Flow is a smart choice for those who only need a standard filter without any “extras.”

Best Washable Air Conditioner Filter:
Clean Air Solutions Max MERV 9

5-Stage CERTIFIED MERV RATED Electrostatic Washable Permanent Furnace A/C Air Filter – The highest MERV rating of any lifetime filter - Traps particles including MOLD POLLEN SMOKE PET DANDER (16x20x1)


  • Pays for itself in year one of use
  • Lifetime warranty from the manufacturer
  • No need to reorder filters or keep track of the size
  • An environmentally friendly option that eliminates waste
  • Static charge captures and holds dust and debris until it is rinsed off


  • Some fitting issues
  • Requires cleaning rather than just throwing away and replacing

What Recent Buyers Report

While it takes some adjusting to get used to a washable filter rather than a disposable one, most consumers are pleased with the Clean Air Solutions filter as a permanent choice. Fitting issues can occur with this filter, so be sure to measure carefully before ordering and contact the manufacturer if yours does not work.

Why it Stands Out to Us

Even though disposable air filters are the “norm” today, this could change in the future, and Clean Air Solutions leads the pack. We love the elimination of waste that comes along with a washable air filter. We are not yet sold that it performs equal to the best disposable filters, but it definitely gets the job done and pays for itself quickly.

Bottom Line

If you never want to find yourself running to the store again because you forgot you were out of air filters, this is the AC filter for you.

Best RV Air Conditioner Filter:
RVAir AC 101G

RV Air RV AC Filter - Air Conditioner Replacement Filters - Travel Trailer Accessories - Air Cleaner for Camper - RV AC Vent Filter - Easy To Install -13.75 x 7.375 x 0.75 in (1 Filter for AC 101G)


  • Affordable and easy to install
  • Made in the USA from recycled materials
  • Captures particles as small as 3 to 10 microns
  • Antimicrobial unwoven polyester filters made to last
  • Creates an effective barrier for harmful particles in the air


  • Reports of restricted airflow
  • Some fit issues for RV owners

What Recent Buyers Report

A few RV owners felt this filter restricted airflow, but the majority of customers were more than satisfied with the filter.

Why it Stands Out to Us

We love a product that is made in America, and once you throw in recycled materials, you have checked the “green” box for consumers, too! Beyond that, we simply love that this filter gets the job done. The last thing travelers want to worry about is the air quality inside their RVs, especially when you are spending so much time on the road. This filter ensures air comfort and quality for travelers.

Bottom Line

To keep your mind on the adventures ahead instead of air quality, replace your RV filter with this RVAir model for good quality at a good price point.

Best HEPA Filter for AC:
Lennox X6675

Lennox X6675 MERV 16 Media Air Cleaner, 1 Count (Pack of 1)


  • Improves air comfort and quality
  • Coconut activated and carbon-coated fiber matrix
  • Eliminates odors along with harmful particles in the air
  • A true workhorse filter, designed to meet HEPA requirements
  • Lennox products backed by more than 100 years of experience


  • Fit problems for some customers
  • Price points exceeding the $100 mark

What Recent Buyers Report

Despite some fitting issues for a few customers, the majority of homeowners are happy with Lennox products, especially for HEPA filtration systems. This filter gets high marks from those especially sensitive to dust as it creates a noticeable difference in terms of dust collecting in the home.

Why it Stands Out to Us

The Lennox filter works with HEPA systems to eliminate even the finest particles from circulating in your home. This filter boasts high-quality construction and solid materials. Plus, we love the odor eliminating features, which are especially helpful in homes with pets.

Bottom Line

If you are replacing a HEPA filter, the trusted Lennox name delivers every time.

Types of AC Filters 

Sizing is not the only area where AC filter shopping can be a bit overwhelming; there are quite a few choices when it comes to types of AC filters as well. We will take a look at the four main categories of filters below.


Because even the long list of standard sizes may not work for every system, customizable filters are an option for those who need a custom fit. An adjustable frame can be used to fit your system, and then the filter material itself is cut and inserted.

Deep Pleat

Filters with a deep pleat are designed to last longer. Those deep pleats maximize the filter's surface area while also allowing for more airflow and cleaning of particles.


Disposable AC filters are the type that comes to mind first for most people as they are the most commonly used. Disposable filters are a popular choice as they are inexpensive, lightweight, and easy to use. Typically, they last from 30 to 90 days, though some disposable filters can now be used for up to six months.


With so many consumers interested in “eco-friendly” products these days, reusable filters that can be washed are also growing in popularity. However, they are more expensive than disposable filters, so they are not as common or accessible as of yet.

How to Clean an Air Conditioner Filter

Even after replacing a disposable filter, your AC system may need additional cleaning. Use a vacuum hose attachment to clean up any debris that has collected outside of the vent, and wipe down the vent with a damp cloth.

If you have a washable filter, the best place to clean it would be in a large sink or shower. Check out this video for a detailed guide on cleaning:


There is more to consider when shopping for air filters than just a bargain price (although that never hurts). You need to ensure the filter you are choosing is available in the appropriate size for your AC system and meets your needs regarding its ability to block contaminants and its overall airflow. A good filter will improve the air quality and comfort in your home, and it could also save you from damaging your AC system and facing expensive repair costs.

People Also Ask

Consumers shopping for AC filters often ask these common questions, so we have provided the answers to make it easier for you to shop for filters and troubleshoot common issues.

What Happens if the AC Filter is Dirty?

The bottom line is your AC will not perform well with a dirty filter and, over time, it could stop performing altogether.

Where is My Air Conditioner Filter?

Your air filter is typically located where the return duct enters the air handler; bear in mind you may have more than one of these in a larger home.

Can I Run My AC Without a Filter?

Technically, the answer is yes. However, we strongly caution against it. You could remove the filter and run to the store to buy a new one without a major problem; however, you should never run your AC without a filter for any considerable time. It will not only mean dirty air circulating in your home, but it could also cause considerable (and expensive) damage to your system

How Do I Know if My AC Filter is Dirty?

Dust near the air vents is a giveaway that your filter is too dirty to continue to trap dust. You may also hear more noise from your AC as it is working “overtime” because of the dirty filter. Allergy sufferers might see a noticeable uptick in sneezing and itchy, watery eyes.

What Happens if Air Filter is Backwards?

In short, it will not be able to do its job. You will be recirculating dirty air.

Can I Cut An AC Filter to Fit?

Technically, yes. And you could, unfortunately, affect the system’s performance by doing so. It is a better idea to order the correct size or have it custom made.

How Long Do Air Filters Last?

The general rule of thumb is that the filter will last 30-60 days; however, homeowners with more severe allergies are advised to change them every 30 days.

Are Cheap AC Filters Better?

A cheap, disposable air filter will get the job done in an allergy-free, pet-free home. Once you introduce allergies or pets into the equation, you would be better served to spend a little more on your filters.

Does Changing Air Filter Improve Performance?

Absolutely! Changing your air filters regularly can improve your AC system's energy efficiency and help keep your electric bills down.