What is a MERV Rating?

What is a MERV Rating?

Air filter performance is measured using different rating systems developed by various organizations. While the names may differ, they all evaluate how effectively a filter captures airborne particles.

MERV (Minimum Efficiency Reporting Value) is the industry standard used in North America and internationally. Developed by the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE), it measures a filter’s ability to capture and retain particles of different sizes.

MERV ratings are generally understood as follows:

• Basic filtration for larger particles such as dust and lint 
• Standard residential filtration, effective for dust, mold spores, and pet dander
• Higher efficiency for finer particles like allergens, smoke, and fine dust
• Advanced filtration typically used in medical, commercial, or high-performance environments
   

MPR (Micro-Particle Performance Rating) is a system developed by 3M for its Filtrete filters. It focuses on capturing very small airborne particles, typically those smaller than 1 micron.

FPR (Filter Performance Rating) was created by The Home Depot and is used mainly for brands sold in its stores. It uses a color-coded numerical scale (typically 4–10) that roughly correlates with MERV performance levels.