Air Filter Types

Air Filter Types

There are many types of filters in the market to choose from for your home, but which one is right for you and your home? Determining which filters you should use really depends on your specific needs as all filters have pros and cons.

Usually, when choosing filters you are choosing between cost and filtration ability. Quite often, more expensive filters exhibit more complex construction and are able to capture finer dust particles, allergens, and other pollutants.

Inexpensive filters perform less particulate filtration and are generally designed for the protection of your HVAC system. As you move down the product line to more expensive filters, you will find they attempt to perform two key roles:

  1. Protecting your HVAC
  2. Removing dust, allergens, and other particulates from the air.

Filters are rated according to which particulate they are able to capture and their dust holding capacity. However, this is where things get confusing. There isn’t just 1 rating system for filters, many rating systems exist! Filters will commonly display a number rating accompanied by one of the following standards to rate the filter:

  1. MERV/ ASHRAE 52.2: Introduced in 1999 Read more on MERV Ratings
  2. ISO 16890: The new global ISO standard introduced in 2017 to replace MERV/ASHRAE
  3. FPR (Filter Performance Rating): A rating system unique to The Home Depot
  4. MPR (Micro-Particle Performance): A rating system created by 3M

Read more about how each rating system stacks up to one another here.

Filter ratings are often dictated by the construction and material of the filter. These are the common types of filter construction that you will find in the marketplace:

Fiberglass filter: A disposable filter that is comprised of fiberglass fibers laid over one another to form the filter media. Typically this filter is reinforced with a metal grating or weaving for support to prevent failure and collapse. Often these filters are the most inexpensive but perform less fine particulate filtering than all other filter types.

Polyester & Pleated Filters: A disposable filter that is made of pleated polyester or similar synthetic medium. These filters contain pleats and may also feature cardboard or metal meshing to maintain structural integrity. The benefits these filters have are that the available surface area for filtering is far larger than flat filters. This benefit allows for finer particles to be trapped by the filter, yet still, maintain the necessary air flow for your system. Pleated filters can effectively filter out pollen, dander, dust mites, mold, and bacteria.

Electrostatic: Some filters are electrostatically charged to pick up particles. This does not mean that they are electrically powered, but they contain a charge that acts a lot like a magnet, allowing the filter to attract particles and make them stick. These types of filter excel at removing fine particulates

HEPA (High-Efficiency Particulate Arrestance): Homeowners often see these types of filters in vacuums or specialty air purifiers. These filters are almost never used in HVAC applications because they impede airflow for HVACs. HEPA filters exceed all other filters for contaminant filtration and are commonly used in hospitals, clean rooms, and airliners. HEPA filters carry a MERV rating of 17-20.

Washable Air Filters:

Washable filters are made of durable materials that can be washed and reused again. These are a cost-effective long-term filtering solution, but typically carry a MERV rating of 1 to 4. They work well at filtering large particles but are ineffective for smaller particles such as pet dander, bacteria, viruses, and smoke.


You should now have a basic understanding of filter options that are available in the market. Next time you make a filter purchase, you will be well equipped to purchase the right filter for your specific environment.

Rating Systems Explained

Rating Systems Explained

If you’ve been shopping for filters, you may have noticed that not all filters are rated by the same rating system. It can be confusing trying to understand how each system stacks up, and how to determine which filter you switch to a differently rated filter.

We’ll try to help you make sense of these differences and make you aware of all the systems currently being used. If you happen to be reading this in the store now, jump down to the graphic below for a quick comparison at a glance.

What systems are there?

Currently, there are four filter rating systems currently in use in North America for rating the filtration ability of home filters.

MERV/ ASHRAE 52.2: Introduced in 1987, this has been a standard the standard for filter rating for a long time. Many products in the North American market still display this rating, but the entire market is already shifting away from MERV as manufacturers are having their filters retested against the new ISO 16890 standards. The MERV scale goes from 1 – 20, but you will often only find MERV 1 – 13 for home HVACs. Read more about MERV Ratings here


ISO 16890: The new global ISO standard was introduced in 2017 to replace the MERV/ASHRAE rating system. This rating system was created to address some of the shortcomings of the MERV system. The new 16890 system does a far better job of accounting for real-world scenarios and places more focus on smaller particles of 3 microns or less. This better aligns testing conditions with the particle sizes found commonly in homes and is a much more accurate rating of the performance homeowners will see. This scale looks at the percentage of particulate removed at various particulate sizes and provides a final classification by combining these scores. Filter ratings will be displayed as a percentage of particulate removed from the air for each particle size group. For an in-depth dive, check out this video [] from Mann+Hummel.


FPR (Filter Performance Rating): A rating system unique to The Home Depot. This system is used on all brands sold through their retail store. Their rating system is color coded and closely numbers relatively align with the MERV rating system.


MPR (Micro-Particle Performance): A rating system created by 3M. This rating system only exists on 3M products and exclusively rates the filter’s ability to capture airborne particles smaller than 1 micron.

The Comparison

This chart should help you to try and understand how filter ratings stack up in within each system. Please note that each system determines their values with their own testing procedures. Not all testing is performed in the same way across each rating system. There will be some subjective discrepancies, but this chart should provide close estimates for comparison.

Breezi helps explain the MERV rating system
Breezi helps explain the MERV rating system

What does MERV mean?

What the MERV?

If you are checking out this article, there is a good chance you need to purchase an air filter and are trying to make sense of all the options that are available. There are many types of filters in the market to choose from, but which one is right for you and your home?

There are many factors to consider when purchasing filters. Usually, when choosing filters you are choosing between cost and filtration ability. Quite often, more expensive filters exhibit more complex construction and can capture finer dust particles, allergens, and other pollutants.

Inexpensive filters perform less particulate filtration and are generally designed for the protection of your HVAC system. As you move up the product line to more expensive filters, you will find they attempt to perform two key roles:

Protecting your HVAC

Removing dust, allergens, and other particulates from the air.
Filters are rated according to which particulate they can capture and their dust holding capacity. Now here is where things get more difficult for the consumer. There are multiple rating systems for filters!

For understanding filter differences for this article, we will be following the MERV rating system that has been predominant in the market for the last 30 years. All other rating systems will have some variations on determining purpose & performance.

MERV stands for Minimum Efficiency Reporting Value. The MERV rating of a filter indicates the minimum particle size that can be filtered. Home filters fall between the range of 1 to 16 on the MERV scale. As the number increases, the filter can remove finer particulate from the air. This table outlines what each level of the filter can capture:


MERV Rating Chart


Give Me the Best!

Now, it would be very common to just assume that you want the highest rated filter, right? Not exactly. As the rating climbs, so does the filter price. Another side effect of higher rated MERV filters is that they tend to more restrictive to air flow and increase the stress on your HVAC system than a lower MERV filter. This can result in a higher energy bill because the HVAC must work harder to move the air through your home.


Your Recommended Filter

The best thing you can do is choose the filter that is right for you and your home based on your environment and personal judgment.

If saving money is the most important thing to you, choose a filter with a lower MERV. You will save money on both filter cost and total energy cost.

If you own pets, smoke, live in a smog heavy area, or are sensitive to airborne allergens – you may stand to benefit the most by using a higher MERV filter.




There is a range of options to choose from when selecting a home filter. The good news is that you cannot make a wrong selection. The most important thing you can do is ensure that you change your filters when they are full and clogged. Filters expire over time and will lose their ability to filter contaminants. A clogged filter will be unable to filter contaminants from the air and will increase system stress which will ultimately lead to higher energy bills and increase the likelihood for repairs.

Improving Air Quality

Improving Air Quality

All homes are susceptible to poor air conditions created by a variety of sources and in some cases, the air we breathe inside can be worse than the air outside!

Pollutants can be released into your home via chemicals and fragrances, tracked in by pets and feet, or can be a byproduct of other conditions such as mold growth when conditions are humid. Here are some tips for many things a home owner can do to improve the quality of the air they breathe.


Not many homeowners look forward to chores, yet regular cleaning is one of the most common steps to maintaining good air quality.


Chemicals and allergens accumulate in household dust. The simplest cleanup method is by using a vacuum with a HEPA filter. HEPA Filters can capture pollutants and ensure dust and allergens do not get blown back out of the vacuum’s exhaust. It is recommended to vacuum two or more times a week. Also, vacuum filters can get clogged! Do not forget to wash or replace your vacuum filter regularly.


Mopping hard floors will pick up any allergens, dander, and dust left behind by a vacuum. Even mopping with water alone can drastically reduce dust and contaminants.


Humidity is one of the greatest contributors to poor indoor air quality. It is important to keep your home’s humidity between 30% and 50%. Mold and dust mites love moisture. If humidity is an issue for you, consider these tips:

  • Use an exhaust fan or open a window when cooking, bathing, and showering.
  • Avoid over-watering house plants.
  • Ensure your clothes drier is vented to the outside of the house.
  • Ensure you have no plumbing leaks or standing water in the house.
  • Consider using a dehumidifier and your air conditioner.

Smoking Indoors

Second hand cigarette smoke is one of the leading contributors to poor indoor air quality. Cigarette smoke contains more than 4000 chemicals and research shows that second hand smoke increases risk for infections, asthma, cancer, sudden infant death syndrome, and respiratory problems. If you must smoke, take it outside.


Both new and old homes are susceptible to radon. Radon is a radioactive, colorless, odorless gas and is the second leading cause of lung cancer. Radon typically rises up through the ground and enter the house through cracks and holes in the foundation and walls. Even granite countertops can emit small amounts of radon. For more information, please see the EPAs Consumer’s Guide to Radon Reduction: How to Fix Your Home

Naturally Smelling Good

Synthetic fragrances in laundry products and air fresheners emit dozens of different chemicals into the air. Even some plugin air fresheners were found to emit up to 20 different VOCs. Under US Federal Law, these chemicals do not need to be labeled on the product – only the word “fragrance” is required to be listed.

  • Look for and use fragrance free products.
  • Stop using aerosol sprays. Furniture polish, carpet cleaners, deodorants, hair sprays can all contribute to higher VOC levels in the home.


Make use of your homes ventilation when possible. Ventilation helps dilute and remove indoor airborne pollutants generated from indoor sources. Many homes have fans that vent to the outside in the bathroom and kitchen. These fans will remove contaminants in those rooms and expel them to the outside.

Natural ventilation can quickly improve indoor air quality. Opening doors and windows will allow fresh air to replace stagnant, stale air in your home. Exercise caution when outside conditions are less than ideal. Avoid opening windows when pollutants such as smoke or smog are present, or when ozone levels are high.

  • Open windows to allow fresh air in on a nice weather day.
  • Bring the outside in! Plants act as living air purifiers. Plants use CO2 (what we exhale) for photosynthesis and emit fresh oxygen as its byproduct.


There are a LOT of factors to consider that can impact your home’s air quality. Fortunately, there are a lot of simple actions you can take to immediately improve your environment. Monitoring your home’s humidity regularly as well as regular cleaning can do wonders for your indoor air quality.

Changing Air Filters

Changing Air Filters

Changing your home’s air filters when needed is the simplest and most important maintenance task a homeowner can perform to ensure their home continues to operate in tip top shape. Dirty filters become ineffective at filtering air and will eventually impede air flow. Clogged filters lead to your system taking longer to regulate temperature and will also cause more resistance against the HVAC fan(s).

First, ensure you are regularly monitoring your HVAC filters on a regular basis. When your filters become dirty and clogged, that is your call to action.

Wall | Ceiling | Floor Mounted filters

  1. Temporarily turn off the fan for your HVAC system.
  2. Find and open the latches on the vent to gain access to the filter.
  3. Dispose the old filter.
  4. If your filter is wrapped in plastic from the store, remove it from the packaging.
  5. Place your new filter in. Ensure the arrows on the filter are point into the duct work.
  6. Close it back up and return your fan back to the on position.

In-Unit Filters

  1. Temporarily turn off the fan for your HVAC system.
  2. Open the filter door for your HVAC/Furnace air handler.
  3. Dispose the old filter.
  4. If your filter is wrapped in plastic from the store, remove it from the packaging.
  5. Place your new filter in. Ensure the arrows on the filter point towards the air handler/HVAC/furnace.
  6. Close the filter compartment door and return your fan back to the on position.


You are now equipped with the know how for keeping your HVAC running optimally. By changing your filters when needed you will save yourself money and repair costs for the life of your system. Check out these additional pro-tips:

  • Save the packaging! You can place your old dirty filter into the packaging to prevent dropping dust and debris during disposal.
  • The arrow always points in the direction of the air flow.
  • Have more questions about your unit? Always consult your HVAC/Furnace owner’s manual.
  • Unsure when you last changed your air filter? Write the change date on the filter.

Or better yet, want to take the guesswork out of filter changes? Get a Breezi powered AirPulse.

Understanding Your Air Filter Configuration

Understanding Your Air Filter Configuration

The HVAC system is often the most important appliance for homeowners. To ensure that your system functions at its best and has a long life, regular maintenance is required.

The number one action a home owner can take is ensuring that filters are changed when needed. Clogged filters cause undue strain on the system and can also increase your monthly energy bill.

Before you can change your filters, you will want to get familiar with where your home’s filters are located, how many you have, and size and type they are. Here are some guidelines to help you determine what type of system you have. If you have any doubts, you can always refer to your owner’s manual. If you do not have a manual, one can always be obtained from your HVAC manufacturer.

Most central HVAC systems will handle its filtration in one of the following two ways:

Air Return Filtration

Many systems have filters that are easily accessed in the home. If you have seen any air vents or grilles in your walls, ceiling or floor – There is a good chance this is the type of system you have. Unlatch your grille for access to the air filter.

If you have this type of setup then you may have more than one filter. Be sure to check all rooms in your home and note all filter locations.

All your air filters should be changed when needed. Do note that each filter may have its own independent schedule for when it needs to be changed based on its location in your home. Not all filters get dirty at the same rate or at the same time.

In-Unit Filtration

If you do not have any air vent grilles in your home, then you probably have an In-Unit filter. Your air filter will be located where your HVAC air handler or furnace is located. These are often located in a closet, attic, crawlspace, or basement. Your filter will likely be behind a removable panel or flap.

If you have a multi-stage filtration unit, please see your owner’s manual for filter details.


Hopefully you have determined how filtration is handled with your unit, you are prepared to perform the most common maintenance task for maximizing your home’s efficiency and air quality.a

OK, Now what?

Find dirty filters? If you found filthy air filters when locating your filters, it may be a great time to change them. Head on over to Changing Air Filters 101 to take the next step.

Are you left with more questions about your specific HVAC system? You can always find answers in your owner’s manual.