You may have wondered, “What is a MERV rating?” if you’ve ever compared home air filters. A MERV rating is a number that represents how effective your HVAC air filter is. The scale ranges from 1-20. The higher the number, the better the filter.

What is a MERV Rating Explained

What Does MERV Rating Mean?

When answering the question, “What is a MERV rating for an air filter?” we should begin with what the acronym stands for. MERV is short for Minimum Efficiency Reporting Value.

The MERV scale was designed to indicated an HVAC filter’s worst possible performance when it comes to removing particles from the air. The higher the number, the better the filter is at removing specific types of particles. The lower the number, the fewer particles are removed.

What MERV rating should I have? Shoot for a higher MERV rating when you shop for an air filter for your home.

MERV Rating Scale

What is a MERV rating scale? The numbers on the MERV scale range from 1-20:

MERV 1-4: These filters are most commonly used for residential furnaces, window AC units, and pre-filtering commercial buildings. They remove pollen, dust mites, sawdust, and textile fibers. The smallest particles removed by filters rated 1-4 on the MERV scale are 10 microns in size.

MERV 5-8: Filters in the 5-8 range are typically used in commercial and industrial buildings. They’re also found in paint booths. In addition to the particles captured by filters 1-4, this style also removes mold spores and concrete dust. The ability to remove particles 3-10 microns in size is the cut off for MERV 5-8 filters.

MERV 9-12: Hospital labs are where you’ll usually find these air filters. They’re used to capture additional particles including coal/lead dust, legionella, and humidifier dust. They filter particles as small as 1-3 microns.

MERV 13-16: Inpatient care hospitals and general surgery facilities require air filters with a rating of MERV 13-16 in order to remove sneeze particles, fumes, smoke, and more. This type of filter can remove particles as small as 0.3 microns.

MERV 17-20: The highest rated MERV filters are used in orthopedic surgery rooms, pharmaceutical manufacturing facilities, and carcinogenic or radioactive housing buildings. The remove virus carriers, carbon dust, radon progeny, and more. They can filter down to 0.3 microns in size.

Best MERV Rating for Home HVAC

Now that you know how to answer what is a MERV rating (you know, next time it comes up at a dinner party…), you may be wondering which type is best for your home.

MERV 13 is considered the best residential HVAC air filter. While the higher rated filter is better for removing contaminates, it may cause your system to work harder as air flow is more restricted. Your local HVAC technician can help you decide which filters your system can handle.

Learn more about HVAC filters…