A low merv rating means that the filter does not remove as many particulates from the air.
Merv air filter rating.
The higher the merv rating the smaller the pores are for air to flow through an hvac filter.
An air filter s merv rating is a scale from 1 16 that describes the minimum efficiency of the air filter.
An air filter s minimum efficiency reporting value merv rating measures how effectively the filter stops dust and other contaminants from passing through the filter and into the air stream.
Filters with a merv 11 rating have a dust spot efficiency of 60 65 and are 30 times more.
Many homes use filters with a merv rating of 1 4 which mostly filter out dust lint and pollen among other larger common particles they do very little to trap small microparticles.
The merv filter rating is the domestic and international industry standard rating system established by the american society of heating refrigerating and air conditioning engineers.
In general filters with a rating of merv.
Below is a chart from john semmelhack showing the percentage of particles removed by size range of particle and the merv rating of the filter.
With a dust spot efficiency of 30 35 they are 20 times more efficient than regular fiberglass filters.
This can create more resistance in airflow than a system is designed to manage thus making it.
Filters with higher merv ratings trap small particles more effectively than filters with lower merv ratings.
For a filter to get the merv 13 rating for example it must filter out a minimum of 90 of the pm10 a minimum of 85 of the pm2 5 and a minimum of 50 of the pm1 0.
The test is based on particle size.
Merv rating chart standard 52 5 minimum efficiency reporting value dust spot efficiency arrestance typical controlled contaminant typical applications and limitations typical air filter cleaner type 20 n a n a 0 30 pm particle size cleanrooms 99 999 eff.
Merv 8 filters remove basically the same particulates as a merv 6 but they are more efficient.
The other two systems were created by 3m mpr and the home depot fpr to differentiate their offerings.
The higher the merv rating the better the filter is at trapping specific types of particles.
The rating system is called ashrae standard 52 2 2007.
On 10 20 pm particles 19 n a n a virus unattached radioactive materials 99 999.
Merv 8 rated filters are high quality filters.
Ashrae developed the merv air filter efficiency rating system.
Ashrae stands for the american society of heating refrigerating and air conditioning engineers.
