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The Best Air Filters for AC Air Flow and Efficiency

Adequate airflow is vital for the function and efficiency of an air conditioning system whether the AC is independent or part of an HVAC system. Without proper airflow traveling into and out of the unit, the unit must work harder, which could lead to equipment damage. Unbalanced air circulation also causes some areas to be cooled while other areas remain warm. The entire interior of a home or office relies on properly functioning equipment and ductwork in order for temperatures to remain constant. That’s why you need the best air filters for AC air flow and efficiency.

Air leakage is also a concern. Gaps or holes in ductwork allow cool air to escape leaving rooms warm. The warm temperature is detected by the thermostat, which causes the air conditioning unit to continually cool incoming air in an attempt to lower the temperature. The cycle becomes unending unless the problem is solved. Along with overworking the air conditioner, utility bills rise through the roof.

The air conditioner’s prefilters are essential for trapping particulates before the unit cools the clean air and transfers airflow to the designated locations. Depending on the type of air conditioning unit, there might be a filter trapping particulates as cool air passes through and enters the space.

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Filters come in all sizes and are made from a variety of materials. The filter types used in common independent air conditioning units are the same type used in household furnaces. As with furnace filters, the products must be changed as frequently as recommended. Otherwise, clogging occurs that does not enable air to flow appropriately.

The ability of a filter to trap various sizes of contaminants varies. Packaging typically states the effectiveness of a filter in terms of the particles the product is designed to capture.

Types of Air Filters

  • Fiberglass filters are the most common type used in HVAC units. They are inexpensive and disposable but require frequent replacement. The filters are crafted using fine strands of fiberglass, which are spun together to create an almost fabric-like appearance. Air easily flows through the microscopic pores. However, the spun mesh captures dust and lint to prevent the particles from entering the unit or expelling into room air.
  • Pleated filters are made from material that is woven tighter than fiberglass. The finished weave is then pleated to increase overall surface area. The larger surface area provides enhanced airflow plus more effective air cleaning. The filters have the ability to capture dust, dust mite debris, pet dander and lint depending on their rating. Various companies offer pleated filters as disposable or washable products. The filters also come in a wide range of sizes to accommodate many different HVAC units.
  • Electrostatic filters are considered top of the line. They are manufactured from fine cotton and paper fibers that generate a static charge during use. The slight charge acts similar to a magnet to attract and trap contaminants. The filters come in disposable or washable varieties in many different sizes. Electrostatic filters are often preferred by homeowners who suffer from allergies.

Importance of Changing Filters

Air conditioner filters must be routinely replaced for a variety of reasons.

  • Ensures unit longevity – Operating an air conditioning unit with a dirty filter for prolonged lengths of time may potentially damage the system. When air cannot flow into the unit, the air conditioner overheats. The fan and motor then work harder to maintain an appropriate temperature inside and out, which eventually results in damage or worn-out components. Regularly changing the filter according to the manufacturer’s recommendations saves homeowners hundreds if not thousands of dollars in repair or replacement costs.
  • Improves air quality – Clean air filters ensure that clean, fresh conditioned air enters the home or workplace. Clean air is of particular importance for young children and elderly adults. Anyone living with chronic respiratory conditions or allergies also need clean air to remain healthy. By regularly changing the filter, indoor air remains void of small and microscopic particles that could impair health.
  • Reduces operating costs – Dirty filters require the air conditioning unit to use more energy to keep components cool. By ensuring that the filter is regularly changed, homeowners may realize savings of up to 15 percent on their cooling costs, as the unit does not have to keep running to stay cool and produce cool air.
  • Better for the environment – If filters are not regularly changed, the air conditioner workers harder, which causes an increase of carbon monoxide and other toxic gasses to escape into the environment. Being eco-friendly is as simple as changing the filter as recommended.

Of all the filter types, plain fiberglass mesh provides the best airflow into or out of the unit. They require frequent replacement but are the least expensive. However, they are the least effective at trapping particulates.

Choosing the Right Air Filter

Air filter packages bear a MERV rating. MERV stands for minimum efficiency reporting value, which translates to the effectiveness of the air filter. The higher the MERV rating, the greater the level of friction created to trap contaminants while ensuring airflow.

The MERV rating system was established by the American Society of Heating, Refrigerating and Air-Conditioning Engineers to represent a filter’s performance. MERV ratings span from one to 16. The number determines the filter’s ability to capture macroscopic and microscopic particles. Higher MERV ratings indicate that fewer particulates are able to pass through the filter and into or out of the air conditioning unit and into room air. The rating indicates the size of the particles trapped in the filter, which range in size from 0.3 to 10 microns.

Comparable MERV and MPR Ratings
MERV MPR Captures
6 300 dust lint and pollen
8 600 all of the above plus dust mites and mold
11 1000 to 1200 all of the above plus pet dander smoke smog and other respiratory irritants
13 1300 to 1500 all of the above in addition to bacteria and viruses


Common particles trapped by tested filters include bacteria, dust mite debris, dust mites, dust, fibers, mold spores, pet dander, pollen, odors and viruses. Filters used for residential use may have MERV ratings of up to 12. Medical facilities commonly use filters having a rating of up to 16. However, the units are specially designed to accommodate the heavy-duty filters.

As MERV ratings increase, the pores of the air filter decrease in size to trap the smallest known contaminants. However, using a filter with a high MERV rating may also reduce the airflow in individual systems, which overworks the air conditioner’s fan while having the potential to reduce indoor air quality. Filters having high MERV ratings also require changing every three months or less. The filters work so effectively that they quickly become clogged, which leads to an inefficient air conditioner if not changed as needed.

Filter packages may also bear an MPR rating, which stands for micro-particle performance rating. The system was developed by the 3M company to denote a filter’s ability to trap airborne particles smaller than one micron. The MPR rating grades the filter on the ability to capture particulates measuring 0.3 to 1 microns in size. As a reference, dust particles range in size from 0.2 to 8 microns while pollen ranges from 7 to 70 microns in size.

Refer to the owner’s manual or consult with the manufacturing company to determine the acceptable MERV and MPR ratings for the individual unit. Filters having high ratings are also more expensive.

The Best Air Filters for AC Air Flow and Efficiency

1) E-Z Flow Air Filter

The American-based Flanders company produces the product and has been in business since the 1950s. The 12-pack of disposable filters comes in a variety of sizes designed to accommodate many different cooling and heating systems. The package of filters weighs 4.25 pounds. Individual filters measure 18 inches x 24 inches x 1 inch.

Each filter contains spun glass fibers within a foil and chipboard encasement. The frame is sealed with melted resin to prevent separation and bending. The package states that the E-Z Flow filters have a MERV rating of 4. The durable design is flexible yet sturdy enough to use as directed.

The filters are manufactured to enable adequate airflow while preventing dust, lint and pollen from entering the home. For optimal airflow and airborne particle protection, the filters must be changed monthly.

2) Percisionaire Ez Flow Air Filter

The inexpensive and disposable Percisionaire filters come 12 to a pack and are also manufactured by Flanders. The package weighs 3.45 pounds. Each filter measures 6 inches x 20 inches x 1 inch. But, various sizes are available. The company also makes customized filters.

A sealed, heavy-duty chipboard frame ensures durability and strength to keep corners from bending and separating. The frame encases the spun glass filament to ensure durability and strength. Each panel is flat and has no metal reinforcements. The filters are designed for optimal airflow while trapping dust and lint.

The Percisionaire filters have a MERV rating of 4 and must be changed monthly.

3) Filtrete Clean Living Air Filter

Filtrete is well-known for its line of filtration products. The Clean Living filters come in a six-pack that weighs one pound. The filters are available in various sizes that include the 20 inches x 24 inches x 1 inch version. The company uses three-in-one technology to manufacture the filters that are designed to trap dust, dust mites, dust mite debris, lint and mold spores to ensure cleaner air. The filters are specially designed for residential use and made using polypropylene.

The filters are pleated to provide a larger surface area for trapping particles while ensuring airflow. The product is created using 15 percent microscopic fiber and 85 percent air. The low density of the filter more effectively allows airflow.

The unique design of the filters involves using an electrostatic charge that attracts airborne particles. The technology enables them to perform better than fiberglass, non-electrostatic and washable versions. They may be used in a furnace, an air conditioner or an HVAC system. The Clean Living filters are rated at MERV 5 and MPR 300 MPR. Each filter lasts for three months before requiring change.

4) FilterBuy Allergen Odor Eliminator Air Filter

The American-made FilterBuy filters come four to a pack. The package weighs 2.6 pounds. The filters in this particular package measure 20 inches x 24 inches x 1 inch. But, all sizes are available or may be custom made to fit. The company also enables consumers to choose filters based on the specific brand of their air conditioner, furnace or HVAC unit.

The filters are pleated and feature a unique activated charcoal carbon coating that is designed to trap and neutralize odors and noxious gases along with VOCs. The filter is stabilized with metallic reinforcements woven around the mesh. The filter is then framed in cardboard around the edges and across the frame for stability.

The filters have a MERV rating of 8, as they are reportedly effective at trapping dust mites, dust mite debris, dust, lint, pet dander and pollen in addition to eliminating odors from the kitchen, pets, smoke or tobacco products. The filters are designed to last for up to three months before requiring replacement.

5) Nordic Pure Pure Carbon Air Filter

The Nordic filters come in a package of six that weighs one pound. Each filter measures 20 inches x 24 inches x 1 inch. But various sizes are available to fit individual units. The pleated filters are created using a polyester base that is infused with activated charcoal carbon. The material is designed to be moisture-resistant to prevent mold and mildew growth. The carbon component effectively eliminates a large variety of odors and toxic fumes from entering the home or office while ensuring sufficient airflow. The filters create an electrostatic charge to trap various contaminants.

The filter is further reinforced with a metallic mesh that is bonded to the medium for added support. The framing consists of recycled paper board around the edges and across the filter itself in order to be environmentally friendly. The Pure Carbon filters have a MERV rating of 8 and an MPR of 800. The Nordic products require changing every one to three months.