Premium air filters are designed to trap indoor contaminants, such as dust, pet dander and pollen, helping to clean the air in your home. In the United States, the MERV rating is the only nationally regulated classification system for air filters. However, some HVAC systems have filters inside the return air ducts spread across several rooms in the house. Some filter brands and retailers use alternative scales, such as Home Depot's Air Filter Performance Rating (FPR) system or the MPR (in 3M Filtrete air filters).Filter ratings evaluate the effectiveness and efficiency of air filters with respect to their ability to remove microparticles and macroparticles from indoor air, thus improving air quality.
We also measure how much each filter restricts air flow, using a differential pressure transducer installed in the air filter. It is important to install the new filter facing in the right direction, look for the arrows on the filter frame that indicate the direction of the air flow. When choosing an air filter, make sure you select one with an appropriate rating based on your home conditions. The MERV rating, MPR system, and FPR system can make it difficult to choose an air filter.
At a certain point, the MERV rating can go too high and cause the central air system to work much harder to push air through the filter. We evaluate how well an air filter removes dust, pollen, and smoke from the air, and see how freely air flows through the filter at any fan speed. When selecting an air filter for your home, it is important to consider all of these factors. The MERV rating is a good starting point for evaluating an air filter's ability to remove particles from indoor air. However, you should also consider other factors such as how much airflow restriction is caused by the filter and how well it removes dust, pollen and smoke from your home's air.
