What is an air filter MERV rating? And, why does it matter?

ASHRAE (American Society of Refrigerating and Air Conditioning Engineers) created a standard test to rate the effectiveness of air filters. With this test, every air filter gets a MERV rating. MERV stands for minimum efficiency reporting value. The higher the MERV rating the more efficient the air filter is at capturing small airborne particles like skin flakes, dust mites, dust mite feces, pollen, etc.

So, is a high MERV rated filter always best? Sometimes. As MERV ratings increase, usually the amount of air able to pass through the system decreases. When the air passing through the system decreases, energy use increases because the system must work harder to do the same thing. When the airflow rate decreases, the normal operation of the system changes in a negative way, which can cause parts to fail prematurely. One of the unintended consequences of more efficient filter is that often, less air gets filtered because of the decreased airflow rate.

Let the indoor air quality experts at Geary Pacific help you determine how high of a MERV rating you need for any application.