The Minimum Efficiency Report Value, commonly known as MERV, is a measurement scale designed in 1987 by the American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE) to provide a more detailed report of an air filter's effectiveness. In short, a MERV rating lets you know what particle size of air an air filter will trap. A higher rating means that the filter can trap smaller air particles, which can be beneficial for households with allergy or respiratory issues. Unlike other scales, which emphasized the need to increase the number of particles passing through an air filter, MERV was designed to offer a balance between particle filtering and energy efficiency. Oven and air filters above MERV 13 are typically found in a hospital environment, where air sanitation is of the utmost importance. Selecting the right MERV rating for your air filter is a delicate balance between the capabilities of your HVAC system and the indoor air quality you want to have.
The higher the MERV rating, the greater the overpressure or air resistance the filter could put in your HVAC system. Therefore, while higher MERV ratings are more efficient, the recommended MERV ratings for residential filters are between MERV 7 and MERV 13. Filters with higher MERV ratings generally have a denser filter material, which means more force is required to push air through the filter. For example, a higher MERV rating doesn't always mean that a filter is the best option for your oven. Nor will it put additional pressure on your oven, since the mesh of the material is not as dense as a higher MERV rating. While the lowest MERV value in each row has no minimum requirement to filter the particle size for that row, it does have stricter requirements for all particle sizes larger than any lower MERV value. In conclusion, understanding what a MERV rating is and how it affects your home's air quality can help you make an informed decision when selecting an air filter.
It's important to consider both your HVAC system's capabilities and your desired indoor air quality when selecting an appropriate MERV rating.