Learning the basics of MERV ratings will you select the best air filter to keep your air conditioner or heat pump running efficiently, while also protecting the system from dirt buildup. A filter with the right MERV (minimum efficiency reporting value) for your cooling system also will boost indoor air quality. With so much at stake, it’s vital that you use MERV ratings to your advantage.
MERV is fairly simple to understand if you understand the relationship between two factors: the size of airborne particulates that a filter will trap, and how much airflow it will allow. The three MERV categories include:
- Low efficiency. Filters in the MERV 1 to 4 range only trap larger airborne particles, 10 microns or larger.
- Mid-range efficiency. Filters rated MERV 5 to 13 trap particles between 0.3 and 10 microns in size.
- High efficiency. Filters in the MERV 14 to 16 range trap particles 0.3 microns in size or larger. By definition, a filter that traps smaller particles also will catch the bigger ones.
MERV goes up to 20, but filters in the 17 to 20 range are designated HEPA filters, and aren’t for use in standard residential HVAC equipment. In general, as an air filter’s efficiency increases, so does its density, and as a result, its potential for impeding airflow.
Using the ratings system
When selecting an air filter based on MERV, you’ll need to:
- Consult the owner’s manual for your air conditioner. It should outline the proper MERV range that is right for the system.
- Work with your HVAC contractor to help you select the filter that will provide the best balance between maintaining air quality and proper airflow.
- Understand that mid-range MERV filters, often pleated to provide more surface area, generally work best in residential applications. As long as you change the filter according to manufacturer recommendations, airflow shouldn’t be a concern.
At NisAir Air Conditioning and Heating we’re happy to assist you with selecting the right MERV filter for your home’s needs. We serve homeowners in Martin, Palm Beach and Indian River counties. Give us call today or visit our website for more information.