What is the MERV Rating on Air Filters and What Does it Mean?

The Minimum Efficiency Report Value (MERV) is a rating system used to measure the ability of an air filter to capture particles larger than 0.3 to 10 microns (µm). This value is useful for comparing the performance of different filters and determining which filter is best suited for your home. The MERV rating lets you know what size of air particles an air filter will catch. A higher rating means that the filter can trap smaller air particles.

The MERV classification system is designed to determine the filter's ability to remove particles from the air. The table also uses percentages based on the chances of an air filter capturing dust particles depending on the micron size. Unlike other scales, which emphasized the need to increase the amount of particles that pass through an air filter, the MERV was designed to offer a balance between particle filtering and energy efficiency. Getting the right oven filter is about matching indoor air quality to the capabilities of your air conditioning system.

Finding filters with the correct MERV rating is essential to ensure that the air is well filtered without overloading the HVAC system. However, a high MERV rating on an air filter generally means that the filter is thicker and that the HVAC system will have to work harder to circulate air throughout the house. The time you'll need to change your air filters depends on factors such as your home location, activity, and the presence of pets. In general, if you cannot see the filter medium under the dust trapped in the filter, it needs to be changed.

You need to change your air filter to maintain the health and efficiency of your home's HVAC system. Particles trapped inside the filter can easily come off when handling it, so placing the old filter inside a plastic bag can help prevent the spread of filter dust. The ASHRAE 52.2 standard describes methods and procedures for evaluating the performance of air filters based on particle size. You should also remember to replace the filter every month, three months, six months, or year, depending on the filter.