What is MERV?

MERV stands for “minimum efficiency reporting value” and the MERV rating is a measure of how effectively a filter removes particles from the air that passes through it. The higher the MERV rating, the more particles the filter will catch.

There’s a flipside to this, though. Filters with higher MERV ratings generally feature denser filtration material, which means more force is required to push air through the filter. It takes exceptionally powerful HVAC fans to effectively push air through the filters at the high end of the MERV rating scale.

The Importance of MERV Rating

A MERV rating is important because it helps you understand an air filter’s effectiveness so you can choose the right one for your particular needs. For example, if you have someone in your home who suffers from allergies, you may want a higher  rating.

The scale also helps you balance your air quality and energy efficiency needs. The rating gives you the worst-case possibility for an air filter, so you can get a good idea of how it will perform. You can get by with a lower MERV rating and save money on your energy bill in some cases.

How Does MERV Affect Indoor Air Quality?

The air in a typical residential structure can contain a number of particulates, including pollen, pet dander, bacteria, tobacco smoke, mold spores, dust mites, and even carpet fibers. A good air filter will help remove many of those contaminants.

Air filters with a  rating between seven and 12 can handle most contaminants in your home’s air. Filters with a rating of 13 or above are usually used only in medical settings.

How Does MERV Impact HVAC System Performance?

It’s important to consider how an air filter will impact the performance of the HVAC system. All forced air systems need a continual flow of clean air to run efficiently.

An air filter helps keep the air going into the system clean. However, an air filter with a high  rating has smaller pores for the air to get through. This can create airflow resistance. A typical residential HVAC system isn’t built to handle high levels of resistance. It can put excessive pressure on the system’s blower fan.

Best Air Filter for Your Home

In general, the best rating for a home is somewhere between 8-10. These filters will capture a large portion of the airborne particles and improve indoor air quality without making your energy costs rise significantly.