What’s a MERV Rating?

150 150 Elizabeth Bonesteel

MERV stands for Minimum Efficiency Reporting Value, meaning this rating evaluates the effectiveness of air filters. Understanding these ratings will help you pick the best filter for you.

The scale ranges from 1-20, meaning the higher the number, the smaller the number of particles that can pass through it. MERV Ratings are set to measure a filter’s performance in a worst-case scenario. But a higher number does not necessarily mean the filter is better for you.

Most residential homes use a filter with a rating between 8 and 13. These filters are designed to capture hair, fibers, plant spores, molds, dust, some forms of smoke and smog, and (according to Wikipedia) pudding mix. These are many of the primary concerns of homeowners (no one likes air-born pudding mix).  Higher rated filters, from 14-20, are primarily used in hospital and healthcare settings where filtering out microscopic particles and bacteria is crucial. While these higher rated filters technically do a better job, they are much more expensive and must be changed more often than other filters. They can also restrict airflow and often won’t fit in residential HVAC systems. Because of this, a filter with a MERV rating between 8-13 is more cost effective and practical for residential homes.

If a filter advertises itself as “hypoallergenic” this typically means it has a MERV rating between 10-13. For people where allergies are a main concern, looking for this rating on your filter will ensure it performs at the level required for comfortable living. Pleated media filters are the most common residential type of filter available, and can have a MERV rating of up to 16 in higher efficiency models. Knowing your air quality needs will help you decide what MERV rating is needed for your home.

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