Air conditioning filters help keep the air you breathe clean by eliminating dust and allergens. The HVAC industry developed the Minimum Efficiency Reporting Value (MERV) rating to help consumers compare the quality of the different filters available. However, the highest MERV rating is not necessarily always the best choice. It is important to take into consideration your budget; the more powerful your filter, the more electricity it requires.

The MERV rating also groups filters based off of their functionality. If you or someone in your family suffers from pet, mold, or dust mites allergies, a minimum MERV score of between 5 and 8 is the best choice. Scores that range from at least 9 to 12 are higher quality filters that trap more airborne particulates. These higher rating filters eliminate automotive emissions, lead dust, and fine flour. A MERV rating of 13 through 16 are usually found in hospitals and help filter out bacteria to cut down on contagions and the spread of disease.

Types of Filters

Fiberglass filters are most commonly used because of their inexpensive price point. These air conditioner filters are the least effective at trapping particles. Pleated filters cover a greater surface area than fiberglass and are slightly more expensive.

Electrostatic filters use electricity to charge trap particles. They are permanent and are also referred to as washable filters. Permanent electrostatic filters are up to 10 more times more efficient than disposable filters. To keep them in their best condition, they need to be rinsed off every three months.

HEPA filters are the most efficient, removing up to 99.97% of particles greater than 0.3 micrometers, however, they are often impractical for residential air conditioners.