Flanders Pleated air filters are among the top performers in the heating, ventilation and air conditioning industry.

Pleated air filters are one of the most popular types of filter available in the heating, ventilation and air conditioning industry and it's not just by chance. These filters offer a very wide variety of characteristics and most suppliers are very happy to provide custom replacement sizes to meet almost any need. They are available over a wide range of efficiencies, media types and frame types. Some even have electrostatic characteristics or even help with odor control. They are the industry standard for contractors because of their durability, availability, cost and effectiveness.

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Why the pleated design is used

There are a couple of very good reasons for the pleated design of these filters and without this design characteristic the filters would be ineffective and unsuitable for use in any heating or air conditioning system.

  • The first reason is the Face Loading (dust is trapped on the surface of the filter material instead of throughout the depth of the material as in media type air filters) characteristic of this filter. Because of this face loading characteristic, there is no distribution throughout the depth of the material to trap particles and this means the filter material must be very efficient because it is very thin.
  • As efficiency increases, so does the restriction to air flow. To compensate for the increased air flow restriction, more filter material is used. Increasing the square footage of the filter material will allow for better air flow and less restriction.

Folding the filter material into pleats increases the surface area of the filter and extends its useful life. If the filter material were used as a flat surface without being pleated it would clog with dust in a matter of days. This would lead to a decline in system performance and could even cause equipment failure if a replacement wasn't installed.

Pleated air filter efficiencies vary greatly

Most pleated air filters are rated at 20 - 30 percent efficient and have a MERV 5 rating. This of course depends on the material being used in the construction of the filter. Nordic Pure manufactures a pleated air filter with a MERV 12 rating which means it is over 97 percent efficient. This is a very high rating for a pleated filter. They are able to attain this very high rating by incorporating electrostatic characteristics in the pleated design. Another factor that makes their filters appealing is they don't support the growth of bacteria, fungi or mold and they capture 97.8% of the microscopic airborne dust, pollen, allergens, mold spores, pet dander, bacteria and particulates carrying bacteria and viruses in the air.


Pleated air conditioner filters and furnace filters are available in 1 inch, 2 inch, 4 inch, 5 inch and even 6 inch thicknesses. The most common sizes used in air conditioning and heating equipment are the 1 inch and 2 inch thick filters. Some specialty filters also use the pleated design. Finding these high end filters at your local hardware store may be difficult but they may be able to order some for you, or you can order them online.

It is important to monitor pleated air filters and change them when required so they do not become plugged with too much dust and restrict airflow through your heating or cooling equipment. Follow manufacturers recommendations.

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Some characteristics of pleated air filters

  • Ratings from MERV 5 to MERV 12 - MERV ratings refer to the size of the particles that the filter captures. A higher MERV ratings mean the filter will trap more dust and allergy causing contaminants.
  • Available from 1 inch up to 6 inches thick - The most common sizes used in heating and air conditioning equipment are 1 inch and 2 inch but they are also available in 4 inch, 5 inch and even 6 inches deep. The deeper the pleat the greater the dust holding capacity and the longer it can remain in the air handler without needing to be changed.
  • Custom sizes are available - Need an odd size? A very common problem with filters is that odd sizes are often required. Manufacturers of pleated air filters are willing to supply custom sizes to meet most needs.
  • Some have electrostatic characteristics - Some of the most efficient pleated filters incorporate electrostatically enhanced synthetic fibers in their filters to achieve very high efficiency ratings.
  • Some are made with carbon or charcoal fiber impingement - These carbon impinged materials are formed into pleats and are used to construct the filter. Carbon is well known for its ability to absorb odor causing contaminants from air and water.
  • There are several common materials used to make pleated furnace filters and pleated air conditioner filters such as cotton, polyester and synthetic blends.

Pleated air filter design

Because there are so many manufacturers of pleated residential air filters there are also many different varieties to choose from. Some have wire mesh on one side of the filter which helps it maintain its shape and prevent it from collapsing due to the pressure of the air passing through it. This is usually found on filters that are made with less rigid materials like cotton. More efficient types do not usually have this wire mesh because the material is rigid enough to withstand the pressures exerted on it from the air.

Are pleated filters good for those who suffer from allergies?

If you suffer from allergies and just can't get any relief, you may want to try a pleated air filter with a higher MERV rating of 10 to 12. These are the most efficient pleated filters available and should help to provide some relief. But upgrading your furnace filter alone may not be enough. It is just one important step in creating an allergy free environment.


Some furnace and air conditioning filters such as fiberglass filters are not very efficient and will only trap the largest of dust particles and don't even do a good job on those, while others such as the electrostatic air filter, HEPA filter and high end pleated filters will remove a much higher percentage of household allergens from the air that passes through them.

Throwaway fiberglass panel filters and filter media vs pleated filters

There are many different types of panel air filters available but many are not worth using in your air conditioner or furnace because they are very inefficient. The worst of these and unfortunately one of the more commonly used are the disposable fiberglass filters. These types of filters are a waste money. The purchase price may be lower but the real cost is poor air quality and higher equipment maintenance costs.


The dust that passes through this type of air filter will end up on your furniture and in the duct system of your hvac unit. If this filter is in an air conditioner or heat pump system, dust will eventually build up on the surface and between the fins of the evaporator coil and restrict airflow. Under certain conditions this can actually lead to equipment breakdown.


Although pleated ac filters with low MERV ratings will do an adequate job of controlling dust in your home they do not work as well as filter media or electrostatic furnace filters. Nordic Pure pleated air filters however are at the high end of the pleated filter category and hold their own when compared to most other air filtration products.


AmSan is an Authorized Distributor for Flanders-Precisionaire Filters. We offer national contract pricing which makes us very competitive. Please contact Steve Kolesar in NH for a quote at skolesar@amsan.com or 603-548-4218 or visit us online at www.amsan.com 

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