Pleated air filters are the most popular type of filter for heating and air conditioning systems due to their efficiency and availability. Unlike media type air filters, they allow dust to become trapped on the surface of the material rather than absorbed into the fibers. The increased amount of material also means that air flow remains unrestricted for longer.

The filters come in a variety of designs, and often custom replacement sizes. Typically, pleated air filters are 1 or 2 inches thick but can be 3, 4, 5, or even 6 inches. The deeper the pleats, the more dust that can be held allowing the same filter to remain in the system without being changed. They also come in a range of efficiencies, media types and frame types including electrostatic and those with odor control.

Filters can be made from a variety of materials including cotton, polyester and synthetic compounds. On less rigid materials, such as cotton, an aluminum wire mesh on one side of the filter is recommended to help maintain the shape and prevent collapsing under air pressure.

MERV ratings (MERV stands for minimum efficiency reporting value) are used to gauge the ability of a filter to remove dust from air that passes through it. Most pleated air filters have a 20 to 30 percent efficiency and MERV 8 rating though some have up to MERV 12 and MERV 13 ratings, and more than 97 percent efficiency. The higher the rating, the fewer dust particles that are able to pass through the filter.

Furnace filters, such as fiberglass panel filters, are far less efficient and only trap some of the largest dust particles. Some types of pleated air filters, on the other hand, may prevent the growth of bacteria, mold and fungi and may be able to capture 97.8 percent of microscopic airborne pollen, dust, mold spores, allergens, pet dander and particulates carrying viruses.

If you would like to learn more about air filters and other issues related to heating and air conditioning systems, please contact us at Around The Clock Heating & Air Conditioning, Inc. We have been improving home comfort in the Los Angeles area since 1967.

Our goal is to help educate our customers in Los Angeles, North Hollywood and surrounding areas about energy and home comfort issues (specific to HVAC systems).  For more information about Pleated Air Filters  and other HVAC topics, download our free Home Comfort Resource guide.

Image courtesy of Shutterstock