This MERV classification chart provides an overview of the best filter for your home. Minimum efficiency values (MERV) measure the ability of a filter to capture particles between 0.3 and 10 microns (µm). A MERV 8 filter is suitable for homes with few occupants and no pets, while homes with more people and some pets need a MERV 11 filter. Before purchasing a new heating filter, be sure to check if your air conditioning system has a maximum MERV rating.
If it does, make sure to buy a heating filter with a MERV rating lower than the system's maximum. Using an air filter with a MERV rating higher than that recommended by the boiler or air conditioner manufacturer may affect its performance. The National Air Filtration Association states that there are 16 MERV values, from 1 to 16, and the efficiency of the tested filter increases as the MERV number increases. Selecting the right MERV rating for your air filter involves a delicate balance between the capabilities of your air conditioning system and the indoor air quality you want.
The worst test score determines the MERV rating, as it is intended to measure the “minimum efficiency” of the filter. You can also find the Microparticle Performance Rating (MPR) system, which ranges from 300 to 2200 and measures the effectiveness of a filter to trap only the smallest particles on the MERV scale (0.3 to 1 micron in size). In general, filters with a MERV rating of 16 or lower are considered filters suitable for air conditioning systems for residential, commercial and general hospital use. Choosing the right MERV rating for your boiler filter has a major impact on indoor air quality, the air conditioning system, and most importantly, your family's well-being.
Remember that there are always other solutions available to improve indoor air quality if your system can't meet the MERV ratings you need.