What Are the Differences Between MERV Ratings?

MERV Ratings

Any HVAC unit requires a filter to keep it safe from damaging particulates and keep it in order. The better the filter, the better air quality you will have, as well as a safer unit. The quality of an HVAC filter is determined by a MERV rating.

A MERV rating, or a Minimum Efficiency Reporting Value, is a rating system that will tell you at a glance how effective any air filter is at its job. This system was designed by ASHRAE and has been used ever since. The numbering tells the arrestance of the filter—the degree of which the filter can remove contaminants from the air.

Take a look at our MERV rating guide:

MERV Rating 1-4

These are the cheapest air filters that you can purchase, and they catch the least amount of contaminants. While pollen, dust mites and other particulates are kept from damaging your HVAC unit, mold spores and finer allergen particles can still come through. If health issues aren't a concern however, these will suffice for most homes, and a filter of some sort is necessary to protect your unit.

MERV Rating 5-8

Mold spores or dust motes that continue to be a problem from before are taken care of at this point. Dust spot efficiency is at 20-35%, and arrestance rests at a comfortable 90%. This is a fine middle of the road option for filtration.

MERV Rating 9-12

Second only to the highest tier, a filter with a rating of 9-12 grants a cleaner than the average air supply at 40-75% dust spot efficiency. Pet dander, fine dust, and even automobile emissions are filtered out at this point. This rating of air filter will help those who have a respiratory illness, such as allergen-related asthma.

MERV Rating 13-16

Outside of HEPA filters, these are the best quality air filters that you can purchase. They will catch nearly anything that will come into your home, including the most microscopic allergen. Dust spot efficiency rests at over 95 percent. If you have a member of your family who is extremely ill, someone with a weakened immune system, or other severe health concerns, you will want to pick up a filter in this category. They are pricey, but they get the job done.

To summarize, a simple rule of thumb for interpreting the numbers is: the higher the rating, the more effective the air filter. Of course, as the filter becomes more effective, so too does the price.

If you have further questions about HVAC filters, or need a HVAC professional to assess your home and help install equipment, don't hesitate to contact Ardmore Fresh Air!


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