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About Air Filter
Efficiency |
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ASHRAE
(American Society of Heating, Refrigeration, and Air-Conditioning
Engineers) standards 52.1 and 52.2 are used to define an air filter's
efficiency. For filters tested in accordance with one or both of these
standards, we list an efficiency rating as described below. Note:
It's common for lower efficiency filters (disposable, washable, and
electrostatic) not to have published efficiency ratings. |
MERV
stands for
minimum efficiency rating value. The larger the MERV number, the more
efficient the filter.
Dust spot efficiency describes a filter's ability to
remove naturally occurring atmospheric dust.
Arrestance describes the percentage of test dust, by
weight, that a filter is able to capture.
Black = Bad ;
Green
= Moderate ;
Red = Good ;
Blue
= Great |
|
MERV Rating |
Dust Spot Efficiency |
Arrestance |
Micron Size of Contaminant |
Typical
Air Filter |
| 1 |
<20% |
<65% |
>10
microns (pollen, sanding dust, spray paint dust, carpet fibers) |
Disposable—
Fiberglass or
synthetic panel Washable— Aluminum mesh or foam panel Electrostatic—
Self-charging panel |
| 2 |
<20% |
65-70% |
| 3 |
<20% |
70-75% |
| 4 |
<20% |
75-80% |
| 5 |
<20% |
80-85% |
3-10 microns (mold, spores, cement dust) |
Pleated |
| 6 |
<20% |
85-90% |
| 7 |
25-30% |
>90% |
| 8 |
30-35% |
>90% |
| 9 |
40-45% |
>90% |
1-3
microns (lead dust, milled flour, coal dust, auto emissions, welding
fumes) |
Bag, Box, Pleated |
| 10 |
50-55% |
>95% |
| 11 |
60-65% |
>95% |
| 12 |
70-75% |
>95% |
| 13 |
80-90% |
>98% |
0.3-1 microns (bacteria, most smoke, insecticide dust, most paint
pigments) |
Bag, Box |
| 14 |
90-95% |
>98% |
| 15 |
>95% |
N/A |
| 16 |
N/A |
N/A |
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