MERV Rating Recommendations for Commercial Buildings

The Benefits of Higher-Rated Air Filters

Clean air supports good health and selecting higher-rated MERV filters for commercial buildings, schools, hospitals and homes offers a wide range of benefits. MERV air filters improve indoor air quality by capturing airborne contaminants, reducing allergens, dust and mold spores. The right MERV air filter can also help extend the life span and improve the efficiency of HVAC systems.

Understanding How Filter Ratings Affect Particulate Capture

The higher the MERV rating, the smaller the particles it can trap. The MERV Rating Chart below illustrates what particulate matter each filter level can capture.

Deciding Which MERV Filter is Right for Your Facility

Every facility has unique needs. Choosing the correct MERV-rated filter will depend upon your facility’s air-quality requirements, compatibility with the HVAC system, and your maintenance protocols. Here are some MERV-rating recommendations for different types of facilities:

Suggested MERV Ratings for Schools and Hospitals

Schools: A MERV 13 rated filter can capture fine particles as small as 0.3 microns. It’s recommended for schools to protect students and staff from airborne pollutants and allergens and help reduce the spread of bacteria and viruses.

Hospitals and Healthcare Facilities require MERV filters with a higher rating. Filters with a MERV number of 13 or higher can capture fine particles, bacteria and other harmful airborne contaminants.

Suggested MERV Ratings for Warehouses and Other Commercial Buildings

Warehouses and Industrial Facilities: MERV filters with a rating of 8 through 11 are sufficient to effectively capture dust, pollen, and mold spores. This level of filtration can contribute to a healthier work environment without overloading HVAC systems.

Office Buildings and Retail Spaces need air quality that keeps employees comfortable while protecting equipment. AC filters with a MERV 11 to MERV 13 rating are recommended for these spaces.

Suggested MERV Ratings for Homes

Comparing MERV rating recommendations for commercial facilities to MERV rating recommendations for residential applications provides a useful benchmark for HVAC professionals. For example, the best MERV ratings for home use are generally considered to be:

Standard Residential Use: Air filters with ratings of MERV 8 to MERV 10 will capture common allergens like dust mites, pet dander and mold spores, and are considered sufficient for most homes.

Homes with Special Concerns: For homes where occupants have allergies, asthma or other respiratory conditions, a MERV 11 to MERV 13 filter is recommended.

What is the Difference Between MERV, HEPA, and ULPA?

MERV is a rating system that indicates the effectiveness of an air filter. This system is based on a numerical scale of one to 20. Filters at the lower end of the scale filter out fewer small particles. Filters at the higher end of the scale filter out very small particles very effectively. HEPA and ULPA filters are highly effective specialty filters which are equivalent to the high end of the MERV scale. In other words, MERV is a rating system for all kinds of air filters and HEPA and ULPA are performance standards for specialty filters comparable to the high end of the MERV scale. The following glossary of terms explains more.

Common Air Filter Terms and Abbreviations

ASHRAE (the American Society of Heating, Refrigerating, and Air-Conditioning Engineers is an international society of industry professionals whose mission is “dedicated to advancing human well-being through sustainable technology for the built environment.” This organization sets standards and guidelines for HVAC systems.

FPR (Filter Performance Rating) is a proprietary numerical rating system from 4 to 10 that indicates how well the filter can capture particles. While there is no published test procedure or publicly available independent testing, the scale is intended to indicate that the higher the rating the better the filtration. Four is considered a good rating and refers to filters that can capture dust, dust mites, and larger pollen particles. Ten is considered a premium rating and can capture very small particles, including those that cause odors.

MERV (Minimum Efficiency Reporting Value) is a numerical rating system developed by ASHRAE. Filters are tested in accordance with ANSI/ASHRAE STANDARD 52.2 on their ability to capture particles between 0.3 and 10 microns in size. The rating scale is 1 to 20; the higher the number, the better the filtration. For example, filters rated between one and four will filter out about 20% of particles that measure between 0.3 and 10 microns, whereas a filter rated MERV 16 will filter out 95% of those particles. The highest efficiency filters can capture 99.97% of particles in the 0.3-micron range.

HEPA (High Efficiency Particulate Air) filters have a MERV rating of 17 or higher and are designed to remove at least 99.97% of particles measuring 0.3 microns or larger. These small particles include pollutants like dust, pollen, mold and bacteria.

ULPA (Ultra-Low Particulate Air) filters are rated at 99.9995 efficiency for the removal of particulate matter measuring 0.12 microns or larger in diameter. These specialty filters are used in environments that require ultra clean air, including cleanrooms, medical research laboratories, electronics manufacturing, and to purify the air in airplane cabins.

How Does MERV Affect Air Flow, Resistance and Blower Capacity?

As the MERV rating of a filter increases, so does the air resistance it introduces into the HVAC system. A blower's capacity to move air is measured in CFM, cubic feet per minute, and decreases as the air resistance (pressure drop) increases. Systems that use filters with a high MERV rating may require a more powerful blower or higher speed to overcome the pressure drop and achieve sufficient air flow to maintain heating and cooling performance. The HVAC system's user manual will usually include recommendations for the filter size and MERV rating.