Minimum Efficiency Reporting Value

"MERV" Ratings

What is MERV? MERV stands for Minimum Efficiency Reporting Value. It is a number from a test method designed by the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE). The number is intended to help people compare filters. Generally speaking, a higher MERV rating indicates better filter performance.



What is the MERV Rating of Carbon Filters?

The main use of the Carbon filters is to remove odors from the air. In that the filters are made with carbon impregnated media and not from electrostatically charged filter media, the Carbon filters do not have an official MERV rating. If odor control is what you are looking for then the Carbon filters are exactly what you need. However, if you are looking for maximum filtration performance then go with the MERV 13 filters.



MERV Value

Average Particle Size Efficiency

(0.3-1 Microns)

Average Particle Size Efficiency

(1-3.Microns)

Average Particle Size Efficiency

(3-10 Microns)

Particles that are trapped:

MERV 1

-

-

Less than 20%

Pollen, Dust Mites, Standing Dust, Spray Paint Dust, Carpet Fibers.

MERV 2

-

-

Less than 20%

MERV 3

-

-

Less than 20%

MERV 4

-

-

Less than 20%

MERV 5

-

-

20%-34%

All of the above and Mold Spores, Hair Spray, Fabric Protector, Cement Dust.

MERV 6

-

-

35%-49%

MERV 7

-

-

50%-69%

MERV 8

-

-

70%-85%

MERV 9

-

Less than 50%

85% or better

All of the above and Humidifier Dust, Lead Dust, Auto Emissions, Milled Flour.

MERV 10

-

50%-64%

85% or better

MERV 11

-

65%-79%

85% or better

MERV 12

-

80%-89%

90% or better

MERV 13

Less than 75%

90% or better

90% or better

All of the above and Bacteria, Most Tobacco, Smoke, etc.



Particles and Their Micron Ratings

(a micron is a unit of measurement in the metric system equal to 1 millionth of a meter in length)


Particle

Approximate Particle Size

(microns)

Bacteria

0.2-1

Dust Mites

3

Hair Spray

10

Human Hair

100

Pollen

10

Mold Spores

3

Tobacco Smoke

1