MERV scores of 5-8 are the most common type of filter recommended by HVAC technicians, and they can be up to eight times more effective than fiberglass filters. These filters are effective in controlling larger particles, such as sanding dust, spray paint dust, lint and carpet fibers, and are applicable in homes and window air conditioning units. However, they don't capture all allergens, and sometimes particles such as pollen, pet dander, and fine dust can sneak through the filter unless you get one with a higher MERV rating. The American Society of Heating, Refrigeration, and Air Conditioning Engineers (ASHRAE) created the MERV 1987 system as part of its ongoing process to update its filter testing standard that was initially published in 1968. The table below shows the minimum threshold at which a filter must operate to obtain a specific MERV rating. But the most detailed system is the minimum efficiency rating (MERV) value designed by ASHRAE. MERV ratings of 1 to 4 mean that the filter will only capture particles at least 10 microns in diameter, which could trap some larger pollen particles, but not most.
MERV 5-8 will trap between 85 and 90% of the particles. We recommend this MERV rating for people with pets, children, or people just looking for better indoor air quality. With the Filter King filter selection tool, you can mark exactly the size, thickness and MERV rating you're looking for. For example, if an air filter can capture at least 20% of E1 particles, 65% of E2 and 85% of E3 particles, it will obtain a MERV 11 rating. In simple terms, it sets the minimum amount of particles a filter must capture to obtain a specific MERV rating. The main difference between the MPR and MERV classification systems is that the MPR classification system focuses on the effectiveness of the filter in removing E1 microparticles from the air.
In contrast, a high MERV rating indicates that the filter does a good job of removing particles from the air. It should also be noted that filters at the lower end of the MERV scale are not even tested for their efficiency in capturing E1 and E2 particles. Based on the defined calculations, as indicated in the Standard, a specific MERV is assigned to the air cleaner. In conclusion, while MERV 5-8 filters are effective in controlling larger particles such as sanding dust and lint, they don't capture all allergens such as pollen or pet dander. To ensure that these smaller particles are removed from your home's air supply, you should opt for an air filter with a higher MERV rating.