Understanding Air Filter Efficiency Rating Systems


There are several types of filter ratings systems in the market today, each created by different organizations. Understanding them can seem confusing but once you have a basic understanding you can confidently select the best filter for your needs.

MERV Rating (Minimum Efficiency Reporting Value) was developed by the American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE), and is the most common rating system for comparing residential air filters. This rating is recognized as an industry standard, both domestically and internationally. The primary focus of MERV ratings is to measure how efficiently a filter removes airborne particles from the airstream as the particles pass through the filter. For residential applications, the scale typically ranges from 1 to 13, with the number serving as an indicator of how well the filter will remove those potentially harmful particles from the air. A higher number indicates a greater level of filtration relative to particle size.

One the easiest, and most cost effective, way of improving the quality of the air in your home is to replace your fiberglass air filter with a pleated air filter.

Originally designed to protect the coils in your furnace or air conditioner, fiberglass air filters simply are not effective on the smallest airborne particles. Replacing it with a pleated air filter can trap 10 times more of these small potentially harmful particles.

Based on current retail prices, the cost of upgrading to from a fiberglass air filter* to a MERV 8 pleated filter** costs only a penny per day.

*  EZ Flow fiberglass air filter, 4-pack, price: $2.99
** Rheem 1" pleated air filter, price: $3.99

FPR (Filter Performace Rating) was developed by The Home Depot for brands sold exclusively through their stores. This color coded system uses a number scale ranging from 4 to 10+. As with the MERV rating, a higher number indicates a greater level of filtration relative to particle size.

MPR (Microparticle Performance Rating) is a system developed by 3M and is solely found on the 3M branded air filters. The numbering system, which ranges from 300 - 2800, rates a filter's ability to capture airborne particles. A higher number indicates a greater level of filtration relative to particle size.

With a basic understanding on filter ratings, you can select the best option with ease. Find the filter that's right for you.