Have you ever wondered what the MERV rating on your furnace’s air filter means? Are you using a filter with the best MERV rating for your needs? Read on to learn more about MERV.
In 1987, the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE), created the standard by which the effectiveness of air filters is measured. This is known as the minimum efficiency reporting value (MERV). A related standard measures a filter’s ability to protect the HVAC system from damage. The MERV standard was created to help improve interior air quality and help improve the energy efficiency of HVAC systems.
Which MERV Rated Air Filter is Best for My HVAC System?
The MERV rating scale ranges from 1-16. Lower quality filters, in the 1-4 MERV range, are typically made of fiberglass. Most residential HVAC systems will use air filters with MERV ratings from 7-12. A higher MERV value of 5-16 would be recommended for commercial buildings. Anything above a 13 MERV rating is considered to be a High-Efficiency Particulate Arrestance (HEPA) filter, often used for hospitals and scientific research lab applications.
In general, filters with higher MERV ratings have smaller pores through which air can pass, while still capturing allergens. However, the smaller pores in these filters can estrict air flow to the HVAC system. This is especially true as the filter becomes dirty through use, which is why it is important to change it as recommended. The restricted air flow can reduce efficiency and increase wear on such components of the HVAC system as the fan and the compressor, and can increase energy consumption.
Better residential filters (5-8 MERV rating) will filter common household allergens such as dust, pollen, mold, and pet dander, while superior residential filters (9-12 MERV rating) will help to remove such things as cigarette smoke, which are more difficult to filter because they contain smaller particles. Many manufacturers recommend using an air filter with an 8-9 MERV rating to maximize the filtration of environmental allergens, while minimizing the strain on the HVAC system.
How Often Should I Change My Air Filter?
As a general reminder, most manufacturers recommend that you change your air filter about every three months. When you change your filter, don’t forget to mark the date on the filter as well as on your calendar. Dirty air filters put additional strain on your home’s HVAC system.
To schedule service or find out the best air filter for your HVAC system, please contact Expert Air and Refrigeration at (512) 255-6525.