What Are MERV Ratings?

Dirty Filter In Home's HVAC Unit|Technician Replacing Air Filter

Minimum Efficiency Reporting Value (MERV) is a measure of the effectiveness of air filters in HVAC systems. These ratings can provide you with the necessary information to choose the right filter for your Monroe, NC home or business. Understanding the importance of MERV ratings and how they impact your indoor air quality can help you achieve the best results for your heating and air conditioning needs.

What Is MERV?

The rating system used to determine MERV was established in 1987 by the American Society of Heating, Refrigerating and Air-Conditioning Engineers, better known as ASHRAE. The National Air Filtration Association has published an online guide that explains ANSI/ASHRAE Standard 52.2 in-depth. In general, MERV categorizes air filters into five tiers based on their filtration capability:

    • MERV 1-4 filtration systems screen out particles of 10 micrometers or greater and are primarily used in window air conditioning units for residential use.
    • Residential, commercial and industrial HVAC systems typically use filters rated from 5-8 on the MERV scale. These filters can remove fungal growth, dust, pet dander and dust mite debris between 3-10 micrometers in diameter.
    • Air filters with ratings of 9-12 can remove particles between 1-3 micrometers and are ideally suited for upgraded home and commercial systems. These filters can stop larger bacteria and most specks of dust and particulate matter.
    • Hospitals are the primary consumers of MERV 13-16 filters, which are designed to remove most bacteria, smoke and droplets from indoor air. These filters can screen out particles from 0.3-1 micrometers in diameter.
    • To screen out particles smaller than 0.3 micrometers, an investment in filters rated from 17 to 20 on the MERV scale is necessary. These filters are usually reserved for use in clean rooms and other environments in which dust can’t be allowed.

Working with an experienced HVAC company is typically the best way to determine which type of filter is best for your needs.

Why MERV Ratings Matter

Finding the right filter for your HVAC system can be a complicated process. Choosing a filter with a MERV rating that is too low can reduce your indoor air quality. Filters that are rated too high for your system can restrict airflow to reduce the performance and the longevity of your heating and cooling systems. Your local heating and cooling company can provide you with the expert guidance needed to ensure the right solution for your specific set of needs.

At Union Services, we offer expert help for all your heating and cooling needs. Our NATE-certified technicians will work with you to provide prompt service and reliable solutions for your home or business. Call us today at 704-233-7029 to learn more about MERV ratings and our indoor air quality services. We look forward to the chance to serve you.