Air Filters 101: Types of Air Filters

What air filters are, how they work and how air purification can benefit you

Don't let bacteria, mold spores, allergens, and other pollutants contaminate your homes air. Get the latest in air purification technology designed trap and even kill the bacteria and pollutants that float through your air. Learn about the different filtration products available and how they work so you can find the right one to clean the air in your home.



Air Purifiers
Control air purity and relieve asthma and allergy symptoms by cleaning your homes air with an air purifier. By trapping pollen, pet dander, and other common airborne allergens with a small air purification system, you'll breathe, feel, and even sleep better.
Furnace and Air Conditioning systems
Your home's heating and air conditioning system is a multitasking powerhouse. It not only keeps the air in your home cool on hot days and warm on cold ones, but it has the power to clean your air as well. Cut down on allergy symptoms and breath easy by installing a purifying air filter in your heating and cooling system.
HEPA Air Filters

High efficiency particulate air, or HEPA, filters are a unique type of air purification systems that must remove 99.97% of particles as small as 0.3 microns to meet guidelines set by the US Department of Energy. Because of their power to remove a majority of airborne particles and allergens, HEPA filters come highly recommended by allergy and asthma experts.

Dry air is hard on our body, leading to itchy eyes, sore throat, and dry skin. It can also be harmful to your home resulting in peeling wallpaper, and cracked paint and furniture. Bring your indoor air back up to an optimal 30 to 50 percent by using a humidifier to add moisture to your air.
UV Air Filters
Ultraviolet (UV) is a spectrum of light just below the range visible to the human eye. With a germicidal wavelength of 253.7 nanometers, ultraviolet light alters the genetic (DNA) material in cells so that microbial particles like bacteria, viruses, and mold can no longer reproduce essentially destroying them.



Shopping for an air filter for your furnace or air conditioning system is complicated. From size to rating, contaminants to media, there are a number of factors to consider. Cut through the confusion and get what you need at a good price with this step-by-step buying guide.


Using the correct air filter size is very important. The wrong size can drastically reduce the effectiveness of filtration and put a burden on the systems hardware. To find the correct size for your application, check your heating or cooling system for a tag or sticker specifying the recommended air filter size. If you are unable to locate such a tag, remove your existing filter and look for a label on the outer frame.


The air filter size will include three measurements: The length, width and depth (for example: 16 x 14 x 4). The air filter size can be listed in two different ways nominal or actual. Nominal size, also called advertised size, is the most common. Its the air filters measurements rounded up to the nearest whole inch (for example, 16 x 14 x 4). Other times, the actual size is used. Just as the name suggests, the actual size is the precise measurements of the filter (for example, 15 ¾ x 13 ½ x 3 ¾).


Filters are made in a variety of thicknesses, typically ranging from one to four inches. A thicker air filter will help to trap more particles, but it may also impede airflow. Check the thickness of your current filter or look at the user manual to be sure what your system can support. If your system will only accommodate a one-inch sized filter, you can increase its effectiveness by getting a pleated filter, checking it at least every 30 days, and replacing it when it's getting dirty even if the timing differs from the manufacturers recommendation.




While there is a right or wrong air filter size, air quality is a personal decision based on individual factors and health needs. If you or a family member has seasonal allergies, choosing a filter that captures pollen and mold will be the right decision for you. Similarly, if dander, mites or tobacco smoke are concerns, select the air filter designed to trap those allergens.

Ratings are key

The MERV, FPR or MPR air filter ratings are designed to help you quickly identify the filter that will best trap the allergens you want out of your indoor air. Look for the allergens on a ratings chart to find the one that meets your air quality needs. And while some filters might have allergens in their name, it's important to read the package carefully to make sure the allergens it captures are the ones you're concerned about.

Air Filter Ratings

FPR (Filter Performance Rating)
Filter performance rating (FPR) is an air filter rating system developed by The Home Depot to takes the guesswork out of choosing from the brands sold in their stores.
MERV (Minimum Efficiency Reporting Value)
The minimum efficiency reporting value â€" or MERV is a rating system developed to evaluate the effectiveness of air filters. MERV measures a filter's ability to capture unwanted airborne particles, as well as the size of the particles.
MPR (Micro-Particle Performance Rating)
Micro-particle performance rating is a metric developed by 3M Filtrete indicating how effectively a filter can capture particles between 0.3 and 1 micron in size.




When it comes to air filters, spending more money does not mean you're buying a better product. Beneath the labels and eye-catching packaging, the products are essentially the same. Two filters with the same rating, made of the same material will perform the same, no matter the brand or price. Aftermarket brands like Tier1 air filters can be a cost-saving option because the filters are made of the same materials and have been quality tested to perform to the same standards.

Exceptions to the rule

There are two key features that will make a difference in performance: pleated and electrostatic charge. While the rating of a flat filter and a pleated one can be the same, the pleated filter will perform better and last longer. Similarly, an electrostatically charged filter will attract particles while a non-charged filter will simply catch particles as they pass by, so even though the rating is the same, the electrostatic charge will remove more from the air. Because of these nuances, it's important to read the product features carefully and compare identical features to find the best value.

Value packs are valuable

Buying in bulk is not only cost effective, but it's time saving and helps to ensure your home will have a uninterrupted flow of clean air. When you have a few spare filters on hand, you can replace the old dirty filter right away, before sneeze-causing allergens have a chance of making their way into your home.

WHAT'S REMOVED: Common Household Air Pollutants

Air filters work to reduce common airborne particles from our indoor air so that allergy sufferers spend less time experiencing symptoms like sneezing, scratchy throat, and itchy eyes. The typical allergens air filters can capture include:
Dander and pet allergens
Pet allergies are often blamed on a cat or dogs hair, when in fact; pet hair is not an allergen. The proteins found in dander and saliva are the actual culprits. These proteins are released in saliva and from skin glands, so when skin and fur is licked, it's getting a second dose of the protein, which dries and then is shed off in the form of dander.
Dust mites
Tiny eight-legged relatives of the spider and tick, dust mites have no eyes or respiratory system. Too tiny to see with the naked eye, a mite is less than half a millimeter ranging from one quarter to one third of a millimeter in size.
Mold and mold spores
Molds are microscopic organisms that belong to the fungi kingdom, so they are neither plant nor animal. When mold reproduces; its seed-like spores are a mere 3 to 40 microns in size invisible to the naked eye.
Pollen is made of very tiny grains and it usually looks like a fine yellow dust. The fertilizing element of a flowering or conifer plant, pollen carries the cells that enable a plant to reproduce. Called pollination, it's responsible for the growth of apples, oranges and other fruits â€" without pollination, trees couldn't grow fruit.
The dictionary describes smoke as, a visible suspension of carbon or other particles in air, typically one emitted from a burning substance. Things like cigarettes, cigars, wood burning stoves, fireplaces and even the kitchen stove can emit carcinogens and other unhealthy particles of carbon into the air, affecting the quality of the air we breathe.


For answers to any filter-related questions, recommendations on the best air filter for your home or general air quality questions, contact us.