Filter MERV Rating - How well is your air filter working?
Are you one of the few people who believe your house air filter is helping you remove indoor air pollutants? Guess again. There are many sources of pollution and allergens in any home. These indoor air pollutants and allergens could come from combustibles, like oil and wood, or from deteriorated furnishings, wet carpet, cleaning products, pet dander, pollen, mold or dust mite debris. Many of these pollutants manifest themselves as dust and can cause miserable experiences for those with pre-existing breathing difficulties.
The most common filters found on residential properties are disposable panels that won’t stop any pollutants or allergens smaller than 10 microns, which makes up less than 20% of the particles in the air. Here is a helpful table which shows the MERV rating in relation to the particles it removes from the air.
| MERV Rating | Average Particle Size Efficiency in Microns |
| 1-4 | 3.0-10.0 less then 20% |
| 6 | 3.0-10.0 49.9% |
| 8 | 3.0-10.0 84.9% |
| 10 | 1.0-3.0 50%-64.9%, 3.0-10.0 85% or greater |
| 12 | 1.0-3.0 80%-89.9%, 3.0-10.0 90% or greater |
| 14 | 0.3-1.0 75%-84.9%, 1.0-3.0 90% or greater |
| 16 | 0.3-1.0 75% or greater |
To give you a frame of reference, a human hair is about 70 microns.
If you want a house air filter that will catch 75% of the particles in the air or more, you’ll want to check for a MERV rating of 16. These filters tend to be used commercially and industrially, but still work great for home owners, especially if you want the best dust control. Unfortunately, with these you’d have to change the filter regularly or the high level of dust can negatively impact the equipment.
A MERV rating is based solely on the number of particles of varying sizes the filter caught in a controlled testing environment. MERV is not an international industry standard but some manufacturers, like 3M, use their own rating system that is not industry standard. So be careful when you go shopping at regular outlet stores.
IAQ Source offers many home air filters with a high MERV rating, equipped to improve indoor air quality throughout your home and remove harmful indoor air pollution. Check out the complete list of whole house air cleaners and potable air cleaners.
