MERV Ratings: Understanding Them Can Improve Your Indoor Air Quality

The quality of the air in your home is an important consideration for the comfort and health of your family. The U.S. Environmental Protection Agency refers to indoor air pollution as “among the top five environmental health risks.” The first step in deciding how to get the best air filtration system for your home is to understand how these products are evaluated. This is where MERV comes in, an HVAC filter performance measure developed by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE).

MERV, which stands for “Minimum Efficiency Reporting Value,” calculates the efficiency of an air filter by measurMERV Ratings: Understanding Them Can Improve Your Indoor Air Qualitying its capacity to capture 0.3 to 10 micron-sized airborne particles. MERV ratings cover the performance of filters used in central forced-air A/C, heat pump and furnace systems, rather than portable room air cleaners. These small models are evaluated with a different measure, known as Clean Air Delivery Ratings (CADR).

Standard MERV ratings range from 1 to 16, with a higher number meaning a greater percentage of particles captured by the filter. A MERV rating of 16 means that the filter captures more than 95 percent of the particles, and the air is clean enough for a medical operating room. The U.S. Environmental Protection Agency states that air filters with a medium MERV rating of 5-13 can have a reasonable level of efficiency at removing small to large airborne particles, without impeding system airflow.

Understanding MERV ratings can help get homeowners get the most appropriate system for their circumstances. If you’re mainly concerned about protecting your HVAC equipment, then a lower MERV rating – 5-8 – may be satisfactory. If air quality is a greater concern, then you’ll want to move up the scale. Just beware that MERV ratings at the top end – 14-16 – may need system modifications in order to work without blocking airflow. Maintaining a smooth flow of air through your cooling or heating system is imperative.

Geisel Heating, Air Conditioning and Plumbing can help you with any questions you may have about HVAC filters, and provide expert advice about the kind of filter you may need. For more information, please contact us. We have been serving the Greater Cleveland area since 1944.

Our goal is to help educate our customers in Cleveland, Ohio about energy and home comfort issues (specific to HVAC systems).  For more information about MERV ratings and other HVAC topics, download our free Home Comfort Resource guide.

For those Do it Yourselfers who would rather take control of your own indoor comfort, you can shop our online store for replacement parts, products and accessories!   

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