Every furnace filter has a Minimum Efficiency Reporting Value (MERV) Rating, which measures how efficiently the filter captures particles of different sizes when your furnace runs. MERV ratings range from 1 (least efficient) to 20 (extremely efficient). Particles are measured in microns and range from carpet fibers (greater than 10 microns) to microscopic bacteria (less than 0.3 microns).
To determine MERV Ratings, air filters are put through two primary tests: The Dust Spot Efficiency Test and the Arrestance Test. Both tests measure the filter's ability to remove atmospheric and larger dust particles from the air. Most high-quality filters can remove 90% or more of injected particles from the air in the Arrestance Test. In other words, they do a good job of removing what they're expected to.
A MERV Rating of 1 would be a basic window air conditioning unit, which filters large particles but isn't meant to clean the air. A 16 is suitable for a hospital surgical environment. Extremely high levels of filtration aren't necessary for the vast majority of residential homes.
MERV Ratings Range
We Offer Several Grades of Filters:
- MERV 8 Air Filters
- MERV 11 Air Filters
- MERV 13 Air Filters
These filters meet the needs of virtually all homes, providing clean, healthy air, and protecting your HVAC equipment.
When it comes to choosing a residential furnace filter, it's best to factor in your household's health needs, the environment (including pets and other potential indoor pollutants), and your budget.
While it's generally true that the higher the MERV rating, the higher the quality, the highest-rated filter isn't necessarily the best choice for all homes. Families with certain health conditions and allergies can benefit from a filter with a MERV rating of 11 or 13, while others can enjoy both affordability and efficiency by choosing 8.Up to a point, a higher MERV rating means a better filter, but filters with very high MERV ratings, which capture extremely small particles, tend to be pricey and are probably a smart investment only for people with an allergy problem and for commercial applications where, for instance, electronic equipment must be protected from small particles of dust.