What does MERV or MERV Rating mean?
Your filters MERV Rating is a good way to help judge the effectiveness of the filter. MERV means Minimum Efficiency Reporting Value which was developed by the American Society of Heating, Refrigeration and Air Conditioner Engineers - ASHRAE. MERV values vary from 1 to 16. The higher the MERV value is the value the more efficient the filter will be in trapping airborne particles. Another consideration is air flow through the your HVAC system. Leaving a dirty air filter in place or using a filter that is too restrictive may result in low air flow and possibly cause the system to malfunction.
ASHRAE recommends MERV 6 or higher
US Department of Energy recommends MERV 13
LEED recommends MERV 8 at a minimum.
See the chart below for filter MERV descriptions.
Minimum Efficiency Reporting Values - MERV ratings
|
MERV Value
|
The filter will trap
Average Particle
Size Effiency
0.3 - 1.0 Microns
|
The filter will trap
Average Particle
Size Effiency
1.0 - 3.0 Microns |
The filter will trap
Average Particle
Size Effiency
3 - 10 Microns |
Types of things
these filters
will trap
|
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%
|
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 |
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 |
Bacteria,
Most Tobacco
Smoke,
Proplet Nuceli (sneeze)
|
| MERV 14 |
75% - 84%
|
90% or better |
90% or better |
| MERV 15 |
85% - 94%
|
90% or better |
90% or better |
| MERV 16 |
95% or better |
90% or better |
90% or better |
|
|
