What is a MERV, MPR, or FPR Rating for AC and Furnace Filters?
MERV Rating is the accepted Minimum Efficiency Reporting Value
for air conditioner furnace filter media as determined by the American
Society of Heating, Refrigerating, and Air Conditioning Engineers, (ASHRAE).
MERV is the primary international air conditioner furnace filter
industry standard and is used for rating the ability of a furnace filter
to capture and hold particles and pollutants. The measurement used in
these ratings is a Micrometer, or micron.
- A micron is one millionth of a meter (0.000001m) and is not visible to the human eye.
- A piece of copy paper is about 100 microns thick.
- A human hair averages 80 microns in diameter.
- Pet dander is 2-4 microns in size and can linger in the air for hours before it settles on a surface!
BestFilters.com uses the MERV Rating system. We have all
standard sizes of AC & Furnace Air Filters available in MERV 8, 10 and 12
ratings. These pleated, 100% synthetic media filters maintain an electrostatic
charge to attract and capture fine particulates. In the average American home,
the most common air filter is a MERV 4. These are usually the fiberglass
furnace filters that you can see through and do not stop particles smaller than
10 microns. These MERV 4 filters will only protect your equipment and will not
help with allergens or even larger particles. We do not recommend MERV 4
filters and do not carry them. We do carry MERV 8, 10 and 12 rated pleated
filters. Most residential systems are well able to use replacement filters up
to MERV 12.
- MERV Rating is the established air filter industry
rating system, but, some companies have developed their own rating
systems, based on the ASHRAE MERV Rating.
- MPR Rating, or Microparticle Performance Rating,
was developed by a large manufacturer (3M) to grade their air filters based
on the ability to filter air particles smaller than 1 micron. The
microparticle performance rating is not considered to be the industry
standard by the American Society of Heating, Refrigerating and Air
Conditioning Engineers (ASHRAE). The published MPR Rating numbering
system is a scale of 0 2700, with their highest published furnace
filter equaling a MERV 13.
- FPR Rating, or air Filter Performance Rating, is a
grading system that uses a color/number system on a scale of 4 (green
circle) to 10 (blue circle). Some of their air conditioner filter
descriptions refer to the MERV Rating and the MPR Rating, but don't
Its important to note that the MERV Rating is the MINIMUM initial
efficiency rating. Its the efficiency rating given to an air
conditioner furnace filter when it is brand new, as the new
air conditioner furnace filter traps more debris, it actually and
somewhat surprisingly, becomes more
efficient at trapping particles as time goes by. Eventually,
though, every air filter will trap the very tiny particles
until it becomes so dirty that air cannot get through and if the filter
is not replaced prior to this point, significant damage may occur to
your HVAC or furnace.