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Published Sep. 29, 2021

It can be easy to completely forget about your HVAC air filter. And that can be a good thing—that means the filter is doing its job properly and your HVAC system is the better for it. It’s keeping out dust and debris, as well as trapping the pet dander, pollen, and other indoor irritants that would otherwise circulate through the system and possibly affect your health and quality of life. For such a small item in your HVAC system, the right air filter really stays busy!

But every three months or so, it’s time to pull out that filter and replace it with a new one to keep your furnace and air-conditioning running smoothly. But how to choose the right one? It begins with the question of which size you need. Once you figure that out, you’ll find endless options in that particular size. We’re here to help you choose the best HVAC air filter based on a variety of criteria that help ensure a cleaner, more comfortable home. 

How We Picked the Best HVAC Air Filters

Methodology

One quick search and you’ll quickly realize that there are more HVAC air filters in more sizes than anyone could possibly test. In an effort to narrow down the options, I considered what might work well for the average homeowner—for instance, I have pets, so I need that pet dander gone, and some in my home have allergies, so pollen is a no-no around here. In addition to pets and allergies, here are some other factors I took into account:

  • Size: All the filters tested here were 20 by 25 by 1 inches, one of the most common sizes in furnace filters today. However, the actual dimensions of most filters are usually smaller by a quarter of an inch on each side; this means that the filter might not fit as snugly as necessary in some newer models, which could lead to air whistling and inefficient performance.
  • MERV rating: An air filter’s minimum efficiency reporting value (MERV) rating measures how effectively the filter stops dust and other contaminants from passing through the filter and into the air stream. Filters with higher MERV ratings trap small particles more effectively than filters with lower MERV ratings. How well does a filter remove the things you need removed from your home’s air? That depends greatly upon where you live. While an air filter with a MERV 8 rating works well just about anywhere, those who live in heavy smog areas might want one rated MERV 11 or higher, and those with immunocompromised family members might choose a MERV 13 filter to remove bacteria and viruses.
  • Airflow: While a MERV 13 air filter might remove everything, that may also mean that the HVAC unit needs to work harder to pull air through the filter. That can lead to problems with the HVAC over time, such as “short cycling” or shutting off prematurely. A lower MERV rating may be in order to ensure proper functioning of your unit.
  • Annual cost. Most filters come in a pack of at least four, with the idea that you will change it every three months and thus have plenty for a year. But that might not be enough, so sometimes a pack of six is much more efficient and might be cheaper.

The Best HVAC Air Filters: Reviews and Recommendations

Best Overall: Aerostar 20x25x1 MERV 13 Pleated Air Filter

Even Filters Smog

Powerful and affordable, this filter can keep your unit in great shape all year. Aerostar

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Why It Made The Cut: This efficient and quiet filter  provides a high level of filtration at a budget-friendly price.

Specs:

  • Rating: MERV 13
  • Size: 19.75 by 24.75 by 0.75 inches
  • Quantity: 6

Pros:

  • Filters out bacteria
  • Affordable price
  • Made in the USA

Cons:

  • Might not provide a snug fit
  • Product packaging might allow allergens in before use

This  MERV 13 air filter from Aerostar features a pleated design made of 100 percent synthetic electrostatic media, which gives it high efficiency while permitting low air resistance, resulting in a quieter air exchange. It filters out microscopic particles that lower MERV-rated filters might miss, such as bacteria, spores, lint, dust mites, viruses, pet dander, and pollen.

Though it’s recommended to change this filter every three months, consider changing it every month during the peak of summer or winter. This product is manufactured in the USA by Filtration Group, a company that makes multiple filtration products for use in homes and businesses.

Best Value: Crisp Filters 20x25x1 MERV 8Air Filter

Great Value for Six

These MERV 8 filters come in a six-pack and combine excellent filtration with ease of use. Crisp Filters

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Why It Made The Cut: With advanced pleat technology that assures better filtration, this filter captures dust, pollen, and more at an affordable price.

Specs:

  • Rating: MERV 8
  • Dimensions: 19.75 by 24.75 by 0.75 inches
  • Quantity: 6

Pros:

  • Extensive pleats assure better filtration
  • Traps particles but doesn’t tax the system

Cons:

  • Doesn’t capture viruses or bacteria
  • Might not provide a snug fit

This MERV 8 filter from Crisp Filters features more pleats than other residential filters, meaning that it can capture more of the debris and allergens floating through your home at a price point that still easily rivals low-performing brands. Use them for up to three months, but for even better operation, replace them every month. 

Expect this filter to remove pollen, dust mites, fine dust, and mold. This filter works well in high-temperature, humid, and moist areas without compromising its performance in removing particles from the air. Simple instructions on the filter itself make changing it a breeze. This product is made in the USA.

Best for Pets: Colorfil 20x25x1 MERV 8 Air Filter

Captures Pet Dander

Using technology originally designed to protect astronauts, the Colorfil filter captures pet dander, pollen, and more. Colorfil

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Why It Made The Cut: This color-changing filter helps clear the air in pet-filled homes and alerts you when it’s time to be changed.

Specs:

  • Rating: MERV 8
  • Dimensions: 19.75 x 24.75 v 0.75 inches
  • Quantity: 4

Pros: 

  • Color-changing technology removes guesswork
  • Great for capturing pet hair and dander

Cons: 

  • Might not provide a snug fit
  • Doesn’t pick up the tiniest dust particles

This unique filter from Colorfil starts out a vivid pink but slowly turns orange and then yellow as it collects pollen, dust, pet dander, and odors. The yellow color signals that the filter is at 25 percent capacity and will need to be changed soon, but it will continue to work, graying as it approaches the end of its useful life. The entire process can take from two weeks to four months. The more pets in a household, the sooner the filter will fill up and become yellow. This MERV 8 filter is made of synthetic fiber and has a pleated design to trap more allergens.

The air filter technology used in this product was originally developed for NASA to protect astronauts in the atmosphere of a spacecraft, and as such, has five times more capacity for air filtration than the leading commercial activated carbon filters. 

Best for Odors: Flanders 20x25x1NaturalAire Odor Eliminator with Baking Soda

A Fresh, Clean House

The power of baking soda turns this filter into an odor-eating powerhouse while capturing everything from pet dander to lint. Flanders

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Why It Made The Cut: The fiberglass pleats are infused with baking soda, meaning this MERV 8 filter can pick up odors better than most.

Specs:

  • Rating: MERV 8
  • Dimensions: 20 by 25 by 1 inches
  • Quantity: 4

Pros: 

  • Baking soda for odor control
  • V-pleats allow for larger surface area
  • Precise fit

Cons:

  • Can be easily damaged during shipment
  • Might inhibit airflow on some systems

With V-pleats that allow for a greater surface area and plenty of infused baking soda, expect this sturdy filter from Flanders to take care of odors in the air while also reducing pollen and other allergens. The wire-mesh backing keeps the filter firm and straight in the unit, and unlike many others, the actual dimensions of this filter match the nominal dimensions, making for a precise fit. The result is a strong filter that stands up to even constant use of the HVAC system and needs replacement about every three months.

This filter has a MERV rating of 8, which means it can pick up most common dust and airborne particles without restricting airflow through a well-maintained HVAC unit. Manufactured in the USA, these filters are built into a frame of recyclable clay-coated molding that resists moisture, making these great for use in high-humidity regions. They can be easily damaged during shipment, so check for any problems promptly when they arrive.

Best for Allergies: AIRx Filters Allergy 20x25x1 MERV 11 Pleated Air Filter

Breathe Easier

A high-end MERV rating of 11 allows this filter to pull away nasty allergens to keep you feeling great. AIRX FILTERS WICKED CLEAN AIR.

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Why It Made The Cut: A MERV rating of 11 is just right for removing typical allergens from the air without restricting airflow.

Specs:

  • Rating: MERV 11
  • Dimensions: 19.50 x 24.50 x 0.75 inches
  • Quantity: 6

Pros:

  • Higher MERV rating for better allergen removal
  • More pleats than most retail air filters
  • Traps smoke and smog

Cons:

  • Might not provide a snug fit 
  • Might restrict airflow in older units

Those who have serious problems with allergies will appreciate this MERV 11 filter from Airx Filters, whose tagline is “Wicked Clean Air.” This filter has more pleats than most filters available to consumers, which means it grabs more of those annoying allergens, such as pet dander, dust mites, mold spores, pollen, fine dust and lint, smog, and smoke. Made in the USA, this filter has sturdy mesh that keeps it from collapsing in the unit, which can be especially helpful if yours is an older unit that may have trouble with airflow when using a higher-rated MERV filter.

The company is a member of the National Air Filtration Association and this filter meets or exceeds the industry standard for performance set forth by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). 

Things to Consider Before Buying an HVAC Air Filter

Many of the points to ponder when buying an HVAC filter went into our reviews Start by determining your priority—do you want to clean your home’s air of dust and other allergens, are you concerned about your city’s smog level, or do you want a filter that can help with odors as well as particulate matter? Once you know your expectations for the filter, you can choose options by looking at the MERV ratings.The MERV is typically printed very clearly on the filter, but some filters might use different rating systems. The MPR, or Microparticle Performance Rating, is favored by 3M for their filters, while Home Depot uses the FPR, or Filter Performance Rating, for those filters that carry the Home Depot name. What they all have in common is that the higher the number, the better the filtration.

But with higher filtration may come the downside of reduced airflow. To capture the tiniest viruses and bacteria, the media that catches those particles must be of a very tight weave, and some older units may have trouble moving air through the media. Consider the difference between trying to breathe through a piece of cheesecloth versus a piece of terry cloth; the cheesecloth doesn’t restrict breathing at all, but the terry cloth certainly does. When you try out a filter, make sure it’s not blocking too much air or the filtration will be negated by the lack of air moving around the house.

Filters come in many different sizes to fit a wide variety of HVAC systems. Check carefully the measurements needed for your system to ensure proper fit. Most filters, like the ones reviewed here, are one inch in thickness, but some systems may require one with a thickness of up to five inches. Remember, again, the more filter the air has to go through, the tougher it gets for the unit to run properly.

FAQs

Q: Are HVAC air filters reusable?

Some of them are. While most filters are the disposable type, some units accept reusable filters that can be cleaned with warm water and dried before using them again.

Q: Does where I live make a difference in my filter?

Absolutely. For instance, those who live in very humid or damp areas will want a MERV rating of 6 or higher to capture mold spores, while those who live in urban areas with a great deal of smog might want a filter with a rating of MERV 11 or higher.

Q: Why is my air filter whistling?

That sound might be a result of air flowing around the filter rather than through it. The air flowing around it means that the filter isn’t fitting snugly and therefore is not  working efficiently. Measure carefully and choose a filter that fits the space. Pay attention to the actual size, not the nominal size.

Final Thoughts

It’s a fine balance between a filter that cleans effectively and doesn’t impede airflow. Look for a filter that removes as much as possible without leading to air restriction. Many newer model HVAC systems can easily handle MERV 11 or higher.

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