When it comes to filtering out pollen, dust, and other household particles, a MERV rating of 7 or 8 is usually sufficient. However, if you suffer from extreme allergies, you'll want to opt for a filter with a MERV rating of 9 or higher. These filters are capable of capturing particles as small as one micron. MERV ratings are used to measure the effectiveness of air filters in removing particles from the air.
The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) recommends using a filter with a MERV rating of at least 13, but preferably 14 or higher. Ratings range from MERV 1 to MERV 20, with the higher number indicating filters that can capture the smallest particles, including many pollen species. Once you've determined the MERV rating you need, you can also consider what type of filter you want. Despite this, air filters with MERV ratings are still widely used in homes, businesses, and other residences in the United States.
Filter technology has advanced significantly over the years, and MERV ratings are designed to help us identify the most effective and efficient air filter options for heating and cooling systems and more. MERV ratings range from 1 to 20, with 1 being the lowest level of filtration and 20 being the highest. Below is a graph showing the different MERV ratings, the particle sizes they remove, and examples of corresponding allergens and other particles. It's important to follow your oven manufacturer's recommendations or consult an HVAC professional to determine which MERV rating is best for your specific system. Filters with higher MERV ratings should be changed more frequently (at least every three months) to avoid restricted airflow that can reduce efficiency or even damage the system. For example, if you're looking for the best filter for allergies (covered in the Best MERV Rating for Allergies section below) or the best filter for homes with pets, you'll want to look for a filter that is rated based on its ability to remove particles smaller than 1.0 microns. This rating does not take into account larger microns.