MERV is an acronym which stands for, Minimum Efficiency Reporting Value. It is Standard 52.2 which was developed by ASHRAE (American Society of Heating Refrigerating, and Air Conditioning Engineers) in the late 1980s to determine the overall efficiency of media air filters. It is used to rate the ability of a filter to remove dust from the air as it passes through the filter. Higher MERV ratings mean fewer dust particles and other airborne contaminants pass through the filter.
These ratings are determined by adding particles of varying sizes, from .3 microns to 10 microns, 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 again 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 filters MERV rating.
MERV ratings range from 1 – 16 and measurements are in microns. Some of the common particles related to MERV ratings are pet dander, insecticide dust, smog, dust, viruses, wood, tobacco smoke, spores, bacteria and pollen.
Some of the most common filters found in residential use only have a merv rating of 1 to 4. These are typically disposable spun fiber panel filters and do not do a good job of filtering the air because they will not stop particles smaller than 10 microns.
Merv 5 to 8 rated filters are a better choice and are more commonly found in commercial applications. These filters will collect particles as small as 3 microns and are a good choice for home owners also.
Filters with a merv rating of 9 to 12 are used in commercial and industrial applications and will stop particles in the 1 to 3 micron range. These filters are a great choice for home owners who want the best dust control possible. When using filters with Merv 9 ratings and above it is important to clean or replace them when recommended by the manufacturer because they will have a negative effect on air flow when they become dirty. This can lead to performance problems and decreased operating efficiency of your heating and air conditioning equipment.
The most efficient filters have merv ratings of 13 to 16 and will stop particles as small as .3 microns. These filters are used in hospitals and other super clean environments. They are also very helpful in residential applications for those who suffer from allergies.
We hope you find valuable information in the table below. If you would like to read more about the different furnace filter options and some of the benefits of each, checkout the some of our other pages. Media Air Filters, Pleated Air Filters, HEPA Air Filters, Activated Carbon Air Filters
MERV Filter Efficiency Guide
|Arrestance||Efficiency||MERV Rating||Types Of Filters||Tested Contaminant|
|60-80%||< 20%||1 – 4||Disposable Panel Filters, Permanent Metal Filters, Fiberglass & Foam Media, Hogshair, Automatic Rolls||Pollen, Spanish Moss, Dust Mites, Sanding & Spray Paint Dust, Textile & Carpet Fibers|
|80-90%||< 20%||5||Pleated Panel Filters, Ring Panel Filters, Synthetic Media||Pudding Mix, Snuff, Powdered Milk|
|90-95%||20-30%||6||Cube Filters, Self-Supported Filters||Dusting Aids, Cement Dust|
|90-95%||25-30%||6-7||Pleated Filters||Hair Spray, Fabric Protector|
|95-98%||40-50%||8||Pleated Filters, Ring Panel Filters, Extended Surface Pocket Filters||Mold Spores|
|98%||50-60%||9-10||Extended Surface Pocket Filters||Welding Fumes, Nebulizer Drops, Coal Dust, Auto Emissions|
|99%||60-70%||10-11||Pleated Panel Filters, Extended Surface Pocket Filters, Rigid Cell Filters||Lead Dust, Milled Flour|
|99%||80-90%||12-14||Pleated MERV 12
Pleated MERV 13 Extended Surface Pocket Filters
|Legionella, Humidifier Dust, Smoke, Copier Toner, Face Powder, Paint Pigments, Insecticide Dust|
|99%||90-95%||14-15||Extended Surface Pocket Filters, Rigid Cell Filters||Sneeze, Cooking Oil|
|NA||95%||16||Rigid Cell Filters||Bacteria, Tobacco Smoke|
Don has been working in the HVAC industry for more than 25 years and shares his experience and knowledge on this site. You can also follow him on: