Choosing the correct air conditioning filter for your home

The air filters for your home air-conditioning system remove impurities from the air that enter your A/C unit. Removal of these impurities (dust, pollen, smoke, etc.) keeps the coils and heat exchangers inside the A/C unit clean and allows the unit to operate more efficiently. The more efficiently the unit operates, the less energy it requires to condition the air—and the less electricity it uses!

The HVAC air filters also are responsible for cleaning the air that leaves your A/C unit, increasing the importance of having filters that purify the air you breathe.

Consider the following three basic criteria when selecting a filter:

Size: Your unit is designed for a particular size of filter for optimum efficiency. Usually, the size will be printed on the filter you are replacing. If you cannot find the size printed on the filter, you can measure the existing filter or filter housing to find the size. See “Finding the Right Filter Size” below.

Cost: Normally, a flat panel filter is less expensive than an extended surface (pleated) filter. However, the pleated filter does not have to be changed as often and can last up to three times longer.

MERV Rating: MERV stands for Minimum Efficiency Reporting Value, a standard developed by the industry to compare filters. The rating ranges from 1 to 16, with 16 being the most efficient and 1 being the least efficient. Filters rated above 12 are not practical for most residential applications. A MERV rating of 7 to 12 offers excellent air filtering qualities for residential units.

Finding the right filter size

Measure the filter: If the filter in the unit fits, purchase the same size. The size is usually printed on the side of the filter. If there is no size printed on the filter, measure the length, width and depth (thickness) of the filter. Remember that the measurements you take are exact, but filters are sold in nominal sizes.

* You can convert your measurements to nominal by rounding each number up to the nearest inch, or when you order, tell the filter specialist your measurements are “exact.”

Measure the opening: If there is no filter in the unit, or you feel the filter is the wrong size, measure the length, width and depth of the opening where the filter is installed in the unit. When speaking to the sales representative about a filter measured in this manner, be sure to tell them that you have “exact” dimensions for either the filter or the opening. This will ensure the filter you purchase fits the way you planned.

We accept returns: If you purchase filters from us and find they are not the correct size, we accept returns and will provide you with the size you need.

* Note: Filters are in nominal sizes, similar to lumber. A filter sold as a 20” x 20” x 1” filter will, in most cases, measure 19 1/2” x 19  1/2” x 3/4”.

Types of air conditioning filters

There are two basic categories of disposable filters, Flat Panel and Extended Surface (Pleated).

Flat Panel Filters
Flat panel filters are made of polyester or fiberglass filtering media; polyester is considered the superior of the two materials. Flat panel filters are the basic product for filtration and are economical, but need to be replaced frequently. The flat panel filter is an excellent choice when there are large quantities of dust and debris to remove from the air. The polyester media holds up well and does an outstanding job of removing particulates.

Disposable Panel Filters
This rigidly constructed air filter maintains its integrity where others fall short. Always the highest quality, Glasfloss disposable panel filters have metal grids on both the air entry and the air leaving sides. The Glasfloss disposable panel filter uses a progressively dense fiberglass or 100% non-woven polyester media to maximize its high dust holding capacity. The Glasfloss disposable panel filter can be used as a direct replacement for filters supplied in original equipment. Standard sizes are available in 1” and 2” depths to accommodate most filter tracks. Any application can be accommodated with our special sizes, available in 1/2”, 1” and 2” depths.

Extended Surface (Pleated) Filters
Made of an advanced material that is either a cotton polyester blend or an all synthetic material, the extended surface filter has filtering media which is pleated. This media looks similar to an accordion. Pleating allows for more filtration media to be placed within the same frame, providing greater surface area to collect particulates and a greater capacity for the whole filter, resulting in fewer filter changes. These filters can last up to three times as long as flat panel filters.

Z-Line Series Pleated Filters
Dustless Air carries the Glasfloss Z-Line Series of pleated filters. All Glasfloss Z-Line pleated filters feature electrostatically charged, 100% synthetic media for high initial and sustained efficiency over the life of the filter. The fibers do not absorb moisture and will not support microbial growth. The Glasfloss Z-Line Series achieves a MERV 7 per ASHRAE 52.2 Test Standard with no increase in initial pressure drop.
The Z-Line Series of pleated filter products include the following:
  • “SB” is our most economically priced pleated filter.
  • “ZL” offers excellent performance and value for a wide range of applications.
  • “HV” is ideal in high velocity systems where maximum square footage of media is necessary.
Specialty and Metal Mesh Filters
Click here to read about metal mesh and specialty filters that we can custom make or order for you.

Same or next day air filter delivery*

We can have your filters ready for pick-up or delivered to your door on the same day or the day after you place your order.

*Please allow more time for custom-manufactured filters and large orders.