Understanding Furnace Filters Ratings

Learn about furnace filters ratings and how to choose the right one for your home. Understand what is MERV rating system and how it works.

Understanding Furnace Filters Ratings

When it comes to furnace filters, the rating is determined by the minimum particle size it can trap, which is measured in microns. The MERV rating system, which stands for Minimum Value of Efficiency Reports, is designed by the American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE) and indicates the size of particles that the air filter is designed to capture. The higher the number, the better the filter will be at trapping small particles. The MERV rating is essential to finding the right oven filter for your home.

A higher rating means that the filter can trap smaller air particles. As air moves through a building's HVAC system, air filters trap and pick up large and small particles, such as dust, allergens and microorganisms. In these cases, a MERV 11 air filter can provide additional benefits and capture a wider range of particles that would pass through a MERV 8 filter. When buying oven air filters, don't confuse MERV with other rating systems that may appear on packaging (especially in large home improvement stores).

Therefore, while higher MERV ratings are more efficient, the recommended MERV ratings for residential filters are between MERV 7 and MERV 13. If someone in your household suffers from allergies or asthma, you should consider buying a higher MERV air filter. The additional benefits of MERV 13 air filters are that they can filter smoke, airborne viruses and smog. They come in many standard sizes, but are generally flimmer and have lower ratings than pleated filters. While you may automatically think that a higher MERV rating means a better air filter, that's not always the case.

Filters with a MERV 6 rating are more affordable and will provide the bare minimum for a home without furry pets.