Best Air Conditioner and Furnace Filters Review and Buying Guide 2019

Your AC and furnace filter is an important protection for your heating and air conditioning system and also for your health. Why?

With the right filter, dirt, dander and other debris are trapped, with two important results!

1. Good for your furnace and AC: They won’t muck up your furnace blower and AC coil. Both problems reduce the system’s efficiency and durability.

2. Good for you: Equally important, those allergens and dust will be removed from the air you breathe. If not filtered, they can cause mold to form on your AC coil and in your ductwork, and spores can be blown around your home. It is crucial to get them out of the air.

What’s In This Guide?

This Air Conditioner and Furnace Filter Buying Guide is loaded with useful details about choosing and using the best furnace filter for your purposes.

But first, we want to let you know about the best air conditioner and furnace filters for your home.

Top 5 AC and Furnace Filters for Allergies and More

This list has something for everyone, whether you need a good-quality basic filter, the best furnace filters for allergies or another specialty type.

Here are the best furnace filters by category.

Important Notes:

1. MERV: The higher the MERV, the better the air filtration. MPR is used only by 3M Filtrete.

2. Size: Each filter comes in all sizes. Select the link, and choose the right size for your furnace.

      Image                    Product

MervFilters MERV 8 Filter

  • 8 MERV
  • Affordable
  • US-made of US material
  • Made in all common sizes

Basic Air Filtration

AIRx ALLERGY MERV 11 Filter

  • 11 MERV
  • Made in USA
  • Highly pleated
  • Sizes from 14x14

for Pet Dander & Minor Allergies

Filtrete Filter, MPR 1200

  • 11 MERV
  • Carbon absorbs odors
  • By 3M
  • Sizes from 14x20

for Allergies & Odors

Canopy Air MAX Air Filter

  • MERV 13
  • Other MERV Options
  • Made in US
  • Sizes from 14x14

For Severe Allergies

Filtrete Air Filter, MPR 2800

  • MERV 14
  • Smoke, Bacteria, Viruses
  • Electrostatic
  • Sizes from 14x20

For Smoke and Viruses

Reviews of the Top Furnace & Air Conditioner Filters

These reviews take you deeper into the details of the top air filters for furnaces and air conditioning.

We let you know why the filters are on our list, what consumers have to say about them and the top features of each.

Best for Basic Air Filtration

#1 MervFilters MERV 8 Pleated Premium Furnace, Air Conditioner and HVAC Filter

Not every home requires high-MERV air filtering. This is the best MERV 8 filter available. It provides standard filtration.

Reason it is on the List: This high-quality filter is ideal for homes with older furnaces that won’t work well with a high-MERV filter. If nobody in your home has serious allergies and you’re looking for affordable, quality filtration, this one is a good choice.

MERV Rating: MERV 8

Features:

  1. Pleated to increase surface area.
  2. Sturdy design allows you to get it into your furnace without damaging it.
  3. Fits all brands of furnace.
  4. Electrostatically charged to attract particles.
  5. Synthetic fibers won’t absorb moisture, so won’t mold or mildew.
  6. Made in the US of domestic materials.

Most helpful user reviews:

  • Best pro review: “Better quality than many of the ‘big-name’ filter brands, in my opinion. Gets the small stuff too.”
  • Best con review: “About ½ inch too small, so it’s a little loose. But does the job.” [PickHVAC editor’s note: Many furnace filters are slightly smaller than described. This ensures they fit without “cramming” them in. Being slightly loose is normal.]

Sizes Available: Square and rectangular sizes from 10x10 to 20x25 including 12x20 and 16x20.

Our Rating: 4.8 out of 5 for quality, construction and efficient 8 MERV filtration.

Best Furnace Filter for Pet Dander & Minor Allergies

#2 AIRx ALLERGY MERV 11 Pleated Air Filter

A MERV 11 filter is considered mid-range air filtering. This filter should help stop allergy-related coughing and sneezing.

Reason it is on the List: This filter does a great job removing common allergens like dust, pollen and pet dander. It’s pretty good on smoke too. If you have moderate allergies, this filter is a good choice. The AIRx Allergy filter also has the best range of sizes, so you’ll find a “perfect” fit.

MERV Rating: MERV 11

Features:

  1. Ideal for mold, dander, pollen, dust mite debris and other allergens.
  2. Heavily pleated for maximum effectiveness.
  3. Made in the US.
  4. Similar to Filtrete MPR800 and 1200 Allergen Reduction and Allergen Defense filters.

Most helpful user reviews:

  • Best pro review: “No fancy packaging, but excellent filtering. I noticed my pet allergies got much better when I replaced our cheap furnace filter with this one.”
  • Best con review: “My furnace is 15 years old. After this filter gets about ‘half-dirty,’ my furnace blower starts short-cycling. This means it is working too hard. I change the filter to a new one, and the problem is solved.” [PickHVAC editor’s note: This is common with older furnaces. If you need the high MERV rating for allergies, then you’ll have to change the filter more often. If you don’t need 11 MERV, then see the MervFilters MERV 8 above.]

Sizes Available: Square sizes from 14x14 to 20x20 and non-square sizes including 14x20, 14x24, 14x25, 16x20, 16x25 and 20x25.

Quality Rating: 4.6 out of 5 for quality design and excellent value for a MERV 11 filter.

Best Furnace for Allergies Plus Carbon for Odors

#3 Filtrete AC Furnace Air Filter, MPR 1200, Allergen Defense Odor Reduction

Filtrete is a 3M brand and makes the widest range of furnace filters. The layer of carbon on this filter makes it ideal for fighting odors.

Reason it is on the List: A layer of activated carbon absorbs odor-causing pollutants from pets, mold, smoke and organic vapors (VOCs).

MERV Rating: MPR – Microparticle Performance Rating – is Filtrete’s system. MPR 1200 is the equivalent of 11 MERV. There’s more on the comparison in the Buying Guide below.

Features:

  1. Activated carbon layer removes odors from pets, cooking, chemicals, smoking and more.
  2. Electrostatically charged to attract and capture pollution particles and other allergens of all sizes.
  3. Claims “25 times more effective in odor removal than other national retail home air filters,” but that is unverified.
  4. Filter-change reminders available by signing up with Filtrete.
  5. Also, offer to save 5% with a subscription to buy these filters with options from 1 month to 6 months.

Most helpful user reviews:

  • Best pro review: “Newly married in my 40s. My spouse likes to fry foods. OK at first, but I can’t stand the lingering smell later in the day or the next day. These filters remove the smell.”
  • Best con review: “Put the filter in carefully. If it is damaged, some of the carbon layer might flake off. Messy!”

Sizes Available: All common sizes like 16x20, 16x25 and 20x25. But few “odd” sizes. For example, there’s no 14x24 and 14x25.

Quality Rating: 4.4 out of 5. Generally well-made. But we’re a bit concerned about the carbon layer being damaged if you’re not careful with installing and removing the filter. Take care, and there shouldn’t be a problem. If your pack of filters comes damaged, refuse it or return it for an undamaged package.

Best Furnace Filter for Allergies

#4 Canopy Air MAX AC Furnace Filter MERV 13

These air conditioner and furnace filters are made in the USA of American-made components.

Reason it is on the List: A MERV 13 filter is the most popular for homeowners with bad allergies. We rated this as the best MERV 13 AC and furnace filter available.

MERV Rating: MERV 13

Features:

  1. Removes mold, dust mite debris, pet dander, pollen, mildew spores, lint, viruses, bacteria and smoke.
  2. Heavily pleated to increase surface area and filtering of allergens and other pollutants.
  3. Built with a sturdy frame, so it slides into place without bending or getting stuck.
  4. Compares to Filtrete MPR 1500 to 1900 Ultimate Allergen Defense, and Honeywell Allergen Elite FPR 10
  5. Synthetic materials won’t absorb moisture and cause mold.
  6. Resists bacterial growth.
  7. Electrostatically charged to attract and trap more particles.
  8. Available in MERV 8 and 11 too.

Most helpful user reviews:  

  • Best pro review: “Pollen is terrible right now, but I’m sleeping better since I installed this filter. Sneezing and coughing greatly reduced too. Highly recommended compared with the 8 merv I was using.”
  • Best con review: “I wanted this filter, but it doesn’t come in the size I need – 18 inches square.”

Sizes Available: Common sizes – 14x14, 16x25, 20x20 and 20x25

Quality Rating: 4.6 out of 5. They’re built with quality materials low in VOCs, so you can use them with confidence that they will improve your home’s air quality.

Best Furnace Filter for Smoke and Viruses

#5 Filtrete AC Furnace Air Filter, MPR 2800, Healthy Living Ultrafine Particle Reduction

Got smoke? VOCs? Musty odors? Pet smells? This 3M air handler/furnace filter might be the answer.

Reason it is on the List: Equivalent to a MERV 14 filter, this one does the best job removing smoke and other fine particles from the air.

MERV Rating: MPR 2800 is Filtrete’s rating that is comparable to MERV 14.

Features:

  1. Ultra-fine particle filtering.
  2. Heavy-duty design with structural wire.
  3. Electrostatically charged to attract and hold smoke molecules and other pollutants.
  4. Clears the air of a wide range of allergens, bacteria and viruses.
  5. Can be purchased with the Filtrete “Awair” air monitor that gives you a readout of air quality measurements. Use the link and select the Awair option.

Most helpful user reviews:

  • Best pro review: “Smokers inhabit apartments on both sides of us. I pleaded with the apartment manager to put these filters in the air handlers. They reduced smoke odor by so much I rarely notice the smell now. Very happy I don’t have to move.”
  • Best con review: “Because it traps more junk, it clogs quicker. You might have to change it more often. I didn’t, and after 2 months my heating bill went up cuz the furnace can’t breathe or something.” [PickHVAC editor’s note: That is definitely one of the concerns with a high-MERV filter. You have to check it more often and change it as needed to keep your heating and air conditioning system working at peak efficiency.]

Sizes Available: Most common sizes and a few odd ones like 20x30.

Quality Rating: 4.6 out of 5. Very good quality. A few users report the filters are a little big, and they have to force them into the slot.

Guide Section

This guide discusses issues that will help you make the right decision when it is time to buy a furnace filter.

As noted, there are two key benefits of a quality furnace filter. First, it will protect the performance and durability of your heating and air conditioning system.

Secondly, it will safeguard your home from allergens and other air pollution.

MERV: It’s Meaning and Importance

Simply put, MERV measures how efficiently the filter removes particles from the air, thereby purifying it.  

MERV stands for Minimum Efficiency Reporting Value.

A good summary of MERV is given by Expert Air and Refrigeration. It’s blog states:

In 1987, the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE), created the standard by which the effectiveness of air filters is measured. The MERV standard was created to help improve interior air quality.

The higher the MERV rating, the higher percentage of particles between 0.3 microns and 1.0 microns the filter will remove.

This chart shows the technical side of it. The following graph gives actual examples of the particles removed by filters with various ratings.

Size and Percentage of Particles Trapped

MERV Rating

0.3 to 1.0 Microns

1.0 to 3.0 Microns

3 to 10 Microns

MERV 8

Less than 20%

Less than 20%

70 to 85%

MERV 9

Less than 20%

20% to 50%

85% or Better

MERV 10

Less than 20%

50% to 64%

85% or Better

MERV 11

Less than 20%

65% to 79%

85% or Better

MERV 12

Less than 20%

80% to 90%

90% or Better

MERV 13

20% to 75%

90% or Better

90% or Better

MERV 14

75% to 84%

90% or Better

90% or Better

MERV 15

85% to 94%

90% or Better

90% or Better

Those are just numbers! What do they mean in terms of real pollutants? Here’s a list of allergens and their sizes:

  • Dust mites – 100+ microns
  • A human hair and pet fur can range from 60 to 80 microns.
  • Pollen ranges from 15 to 200 microns.
  • Mold spores are 10 to 30 microns.
  • Dust and dust mite debris ranges from .5 to 10 microns or larger.
  • Pet dander (which is the same substance as most, but not all, dust) is .5 to 10 microns.
  • Bacteria are .2 to 3 microns or larger.
  • Smoke - .01 to .2 microns

OK, here’s an infographic that makes the numbers a lot clearer. It shows common MERV ratings and the types of pollutants and allergens they remove from the air.

Choosing the Right MERV Rating

The most common MERV ratings are 6, 8, 11 and 13. There are no MERV 6 filters on our Top AC and Furnace Filter List because they don’t trap enough allergens and other pollutants.

Best MERV Ratings for Allergies

As you can see, the best furnace filters for allergies have a MERV rating of at least MERV 6, but we recommend a rating of at least:  

  • MERV 8 for No allergies or Light Allergies
  • MERV 11 for Moderate Allergies
  • MERV 13 for Severe Allergies

We’re often asked what is the best MERV ratings for furnace filters.

The answer depends on quite a few things discussed here, but top of the list is what type of allergies you’re trying to clear from the air in your home. That infographic should help you decide.

Furnace Filters and Allergies

Here are best uses for filters with the common ratings:

MERV 6 – This level is 8 times more efficient at removing particles than spun fiberglass filters. However, a MERV 6 filter should not be used anyone in your household has asthma or allergies.

MERV 8 – These air conditioner and furnace filters offer good basic filtration – 20 times better than a fiberglass air filter.

MERV 8 filters are acceptable for those with minor and occasional allergies, mostly pet allergies. Pollutants removed are lint dust, pet dander, mold spores, fine dust and dust mite debris (dust mite feces and decaying mites).

MERV 11 – This is a good filter for those with moderate allergies. It is 30 more effective than fiberglass at removing allergens and pollutants.

A MERV 11 filter removes everything an 8 MERV filter does plus auto emission gases.

MERV 13 – A filter with this rating the best furnace filters for allergies, especially when they are severe.

These filters remove everything a MERV 11 filter does plus fireplace smoke, tobacco and marijuana smoke, odors, bacteria and very fine dust.

What is the best MERV rating for furnace filters?

If you or someone in your home has allergies, a MERV 11 or 13 filter should be strongly considered.

MERV, MPR and FPR

Two brands use their own rating. We’re not sure why, but it seems they’re attempting to set themselves apart. The result is more confusion than anything.

3M Filtrete uses MPR: Microparticle Performance Rating

Honeywell uses FPR: Filter Performance Rating

Basically, MERV, MPR and FPR are synonymous or at least so closely equivalent that the differences is meaningless.

In the literature for Filtrete and Honeywell furnace filters, the equivalent MERV is often given.

Here are the comparisons:

MERV 8 = MPR 600 and FPR 5

MERV 10 = MPR 1000 and FPR 6

MERV 11 = MPR 1200 and FPR 7

MERV 12 = MPR 1500 and FPR 8 or 9

MERV 13 = MPR 1900 and FPR 10

MERV 14 = MPR 2800. You’ll have to ask Filtrete why it escalates the number so much between MERV 13 and 14. Again, it is more confusing than useful.

FAQs

Here are common questions about air filters for furnaces, air conditioners and air handlers.

1. Why do so many labels call them AC or air conditioner filters when the air conditioner is outside?

Because when the air conditioner is running, they filter the air just as they would if the furnace were running. In fact, the furnace blower is running, but the burner isn’t firing. The filter is just as important during summer cooling as winter heating.

There’s a second important reason. A key component of the air conditioning system is housed in the furnace or connected to it – the indoor coil. A good furnace filter will prevent the coil from becoming clogged with hair, dust and other debris. When it does get clogged, it runs inefficiently, and that will cost you money on energy bills. A dirty coil will also break down more easily than a clean one.

Note on heat pumps: If you heat and cool with a heat pump, then you have an air handler. And, of course, it requires these types of filters too.

2. Are furnace filters like HEPA filters?

They’re similar but don’t remove as much of the very fine particles from your air.

See the MERV Ratings table above for comparison. A true HEPA filter removes 99.97% of particles .3 microns and larger. MERV 8 through 12 removes less than 20% of those particles, and it goes up from there. A MERV 13 filter removes up to 75% of pollutants that size.

3. Would an Air Purifier Be Better?

This is an interesting question.

Your furnace or air handler needs a filter, of course.

But should you also have one or more air purifiers in your home?

We recommend considering air purifiers if:

  1. You have shedding pets (dogs, cats, rabbits, etc.)
  2. Anyone in your home has allergies
  3. Anyone smokes (cigarettes, pipe, cigars, cannabis, etc.)
  4. You have a fireplace and it leaves lingering smoke odors
  5. Cooking odors are common in your home, and you find them unpleasant
  6. You live in a dusty environment or an old home/building with musty smells

Our Air Purifier Reviews and Buying Guide has comprehensive details about air purifiers. It’s a good place to begin your research. We’ve also completed air purifier brand reviews of top brands and guides to the best air purifiers for common allergens – dust, pollen, mold and more. Choose the Air Purifier tab at the top of the page to get started.

4. What are the best furnace filters for allergies?

A MERV 11 or MERV 13 filter should be used for moderate or severe allergies.

5. What is the best MERV rating for furnace filters?

MERV 8 is a good rating for basic air filtering when allergies are not an issue.

MERV 11 is a better when your home has known allergens such as pet dander, mold spores, pollen and dust. If anyone has allergies, this is the lowest MERV rating recommended.

MERV 13 is the best choice when heavy allergens are present and someone in your home has allergies.  

6. How often should the furnace filter be changed?

Most manufacturers recommend that you change the filter every 90 days or more often.

To be more precise, we recommend changing it based on need:

  • 3-4 months: Homes with just one or two people and no pets (or 1 person and a pet) and a generally clean home.
  • 2-3 months: Homes with 2-3 occupants (human or pet) when minor dust, pollen and other pollutants are an issue.
  • 1-2 months: Larger households with one or more pets and other sources of pollution like smoking, mold or a dusty environment.

Remember too that the worse the level of pollution or allergens, the higher MERV rating your filter should be.

7. Why doesn’t my filter fit tight?

There is a difference between label and actual size.

The nominal size is the size your furnace manual says the filter should be – and how the filter is labeled.

The actual size will be slightly smaller than the nominal size. For example,

  • Nominal size = 20 x 25 inches
  • Actual size = 19.5 x 24.5 inches

Filter manufacturers make them a little smaller than they “should be” to be sure that you can fit them into the filter slot.

Next Steps

If we’ve done our job, you have a better idea of what MERV is and the right MERV rating for your home based on the needs of your household.

If you’d like to learn about the best AC and furnace filters in the MERV rating you need, we’ve compiled them in our list of the Best Air Conditioner and Furnace Filters. The MERV rating of each is included.

Thank you for reading this furnace filter buying guide! If it has been useful, please consider sharing it on social media for the benefit of others. 

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