What MERV Rating Should I Choose for My Air Filter?

When choosing an air filter for your home or business, it's important to consider the Minimum Efficiency Reporting Value (MERV) rating. Learn more about how different ratings affect your indoor air quality.

What MERV Rating Should I Choose for My Air Filter?

When it comes to air filters, the MERV rating is an important factor to consider. MERV stands for Minimum Efficiency Reporting Value, and it is a measure of the filter's ability to trap particles in the air.


filters trap 80 to 89 percent of average 1.0 to 3.0 micron particles, with an average particle size efficiency of 90 percent or better. This means that a MERV 11 filter is just as effective as a MERV 12 filter, so you can get decent results with either one.

However, a MERV 12 filter that is only 1 inch thick is likely to be more restrictive than a 4 inch thick MERV 12 filter. In general, filters with a MERV rating of 16 or lower are suitable for air conditioning systems in residential, commercial, and general hospital settings. It's important to monitor your air filter and change it periodically with the right MERV value for your home and family. Using an air filter with a higher MERV rating than recommended by the boiler or air conditioner manufacturer can actually impair its performance.

A MERV 5 filter traps up to 34%, the MERV 6 does so between 35 and 49%, the MERV 7 avoids it up to 69% and the MERV 8 traps up to 85% of the particles. If you are not able to use a filter with a high MERV (12+) content for boilers or air conditioners, you may want to look into air purifiers. When trying to determine the correct MERV rating for your air filter, it's important to keep in mind that an oven filter's MERV rating indicates its minimum capacity. A filter with a lower MERV rating could trap fewer particles and contaminants compared to one with a higher rating.

Filters in the MERV range of 5 to 8 can also trap particles between 3.0 and 10.0 microns in size, but are more efficient at doing so. Whatever MERV classification you choose, it is essential that you replace the filter periodically to keep your oven in optimal condition for years to come. High-efficiency particulate air (HEPA) filters trap the smallest particles at a speed even faster than MERV 16 and are typically used in surgical operating rooms, clean rooms, and other settings that require absolute cleaning. The goal of using a MERV 12 or higher filter is better indoor air quality: cleaner, more breathable air for everyone, especially those with allergies, asthma, COPD, etc.

If you have any questions about what is the best MERV rating for your furnace or air treatment system, this information should help answer them.