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What does MERV Ratings mean to me?

What does a MERV Rating mean to me?

The acronym MERV stands for "Minimum Efficiency Reporting Value." MERV ratings are used to rate the ability of an air cleaner filter to remove dust from the air as it passes through the filter. MERV is a standard used to measure the overall efficiency of a filter. The MERV scale ranges from 1 to 16, and measures a filter's ability to remove particles from .3 to 10 microns in size. To give you an idea of the scale of a micron, 100 microns is about the thickness of a piece of paper or a human hair. Filters with higher ratings not only remove more particles from the air, they also remove smaller particles.

MERV ratings are determined by adding particles of varying sizes into a controlled testing environment. The particles are added upstream of the test filter and a laser particle counter samples the air before it enters the filter and after it leaves the filter. The two particle counts are compared to calculate the Particle Size Efficiency of the tested filter. Once this is determined, a MERV Parameters chart is used to determine the MERV rating.

See the MERV Rating Chart below for more information about the difference in performance between filters with different MERV ratings.

What does a MERV Rating mean to me?

MERV Rating	Dust Spot Efficiency*	Typical Controlled Contaminant	Applications	Air Filter Types
1	<20%	>10 micron Particle Size Pollen, Dust Mites, Sanding Dust, Textile Fibers, Carpet Fibers	Minimal Filtration Residential Window A/C Units	Throwaway – Disposable fiberglass or synthetic Washable – Aluminum Electrostatic – Self Charging
2	<20%
3	<20%
4	<20%
5	<20%	3-10 micron Particle Size Mold Spores, Hair Spray, Fabric Protector, Dusting Aids, Cement Dust	Commercial Buildings Better Residential Industrial Workplace Paint Booth Inlet	Pleated – Disposable, extended surface area Throwaway – Disposable synthetic panel
6	<20%
7	25-30%
8	30-35%
9	40-45%	1-3 micron Particle Size Legionella, Humidifier Dust, Lead Dust, Auto Emissions, Welding fumes	Better Commercial Superior Residential Hospital Laboratories Welding Booth Inlet	Bag Filter - synthetic media, typically 6”-36” deep Box Filter – cartridge, typically 4” deep
10	50-55%
11	60-65%
12	70-75%
13	89-90%	.3-1 micron Particle Size All Bacteria, Most Tobacco Smoke, Proplet Nuceli (Sneeze)	Superior Commercial General Surgery Hospital Rooms Smoking Lounge	Bag Filter - synthetic media, typically 6”-36” deep Box Filter – cartridge, typically 4” deep
14	90-95%
15	>95%
16	>95%