Since its introduction in 1987, homeowners have become familiar with the standard air filter ratings offered by the MERV scale. This acronyn stands for minimum efficiency reporting value. This system offers a way to compare one filter against each other, no matter the manufacturer or size.

This rating scale runs from 1 to 20. As the scale goes up, the air filter’s ability to handle microscopic particles gets better. A flat panel fiberglass filter is usually between 1 and 4 on the MERV scale. A pleated residential filter runs between 8 and 12. Filters used in hospitals run in the 16 to 20 range, which equals HEPA filtration.

A Scale Different from MERV?

This scale, created by the American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE), is the industry standard. Most manufacturers offer MERV ratings on their filter packaging for consumer convenience. However, you may find an air filter package that doesn’t have it. If it’s the industry standard, why would you find a package with out it?

Every once in a while, an air filter manufacturer will come up with the idea of creating their own scale. They’ll replace the MERV rating on their package with their custom scale. Quite often the scale will have numbers much like the MERV system, but they won’t match it. This leaves consumers confused and not sure which filter they should buy.

What Should Consumers Do?

If you come across an air filter package without the MERV rating listed, find another manufacturer, if possible. With the standard MERV scale, you know what you’re getting. With a non-standardized manufacturer scale, you don’t know what you’re getting.

For a residential air filter, go with a MERV between 8 and 12 for the best air filtration. Going below that will allow common allergens and mold spores to continue circulating, while going above that will put too much strain on your air handler or furnace blower.

If you need more information on the MERV rating of your residential air filter, contact us at Senica Air Conditioning, Inc.. We’ve served Tampa and St. Petersburg since 1992.

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