What is a MERV Rating?

MERV stands for Minimum Efficiency Reporting Value. The MERV rating was developed by the American Society of Heating, Refrigeration, and Air Conditioner Engineers; ASHRAE for short. This rating evaluates the effectiveness of air filters. In order to pick the best air filter for your household, you must understand the MERV rating.

The MERV scale ranges from 1-16. The higher the number, the smaller the number of particles that can pass through it. MERV Ratings are set to measure a filter’s performance in a worst-case scenario.

Most residential homes use a filter with a rating between 7 and 12. These filters are designed to capture hair, fibers, pet dander, plant spores, molds, dust, some forms of smoke and smog, and other small particles (like pudding mix!). These filters cover the primary concerns of homeowners.

So the higher the number the better the filter?

A higher number does not necessarily mean the filter is better for you. Higher rated filters, 13-16 on the MERV scale, are primarily used in hospital and healthcare settings where filtering out microscopic particles and bacteria is crucial. While these higher-rated filters technically do a better job, they are much more expensive and must be changed more often than other filters. They can also restrict airflow and won’t fit in residential HVAC systems. Reducing the airflow in your house can lead to problems bigger than a few missed particles.

Unless you have the need for an industrial filter, a filter with a MERV rating between 7-12 is more cost-effective and practical for residential homes. When installing an air filter in a residence you are unfamiliar with, we recommend starting with a MERV rating of 11 and adjusting from there based on your preferences.

Hypoallergenic filters

If a filter advertises itself as “hypoallergenic” it typically means it has a MERV rating between 10-13. For people where airborne allergies are the main concern, looking for this rating range on your filter will ensure it performs at the level required for comfortable living. Pleated media filters are the most common type of residential filters available. They can have a MERV rating of up to 16 in higher efficiency models.

Knowing your air quality needs will help you decide what MERV rating is needed for your home. Regardless of what filter you use, changing it consistently is extremely important. Leaving a dirty air filter in place for too long can cause damage to your HVAC system. If you have any questions regarding your MERV rating or are having trouble with your air filters, schedule an appointment with us today.