MERV stands for Minimum Efficiency Reporting Values and is an industry-created
standard that evaluates the efficiency of air filters. The MERV rating of
any particular air filter ranges on a scale of 1 to 16, with a filter rating
1 being the least efficient and a filter rating 16 being the most efficient.
For example, a filter with a MERV rating of 3 would only be able to remove
a small percentage of the largest airborne particles, while a more efficient
filter with a MERV rating of 15 would remove even the tiniest airborne particles.
While it is important for the quality of the air in your home to choose the
most efficient filter possible, it is not always as simple as buying a filter
with the highest MERV rating. Because the pores allowing for air flow in
a highly-rated MERV filter are very small, the filter creates more resistance
against air flow and may put too much pressure on the fan of your furnace
or air conditioning unit. It’s important to choose an air filter with
the highest MERV rating that your particular unit will allow for maximum
air flow. Information about specific MERV ratings and recommendations for
your furnace will generally be included with the documentation that came
with your system.
We recommend choosing an air filter with a MERV rating between 8 and 11 for
most residential furnace and AC units in order to adequately remove airborne
contaminants. If your system can handle a filter with a higher MERV rating,
you may wish to use a filter with a rating of 12 or 13 for even greater contaminant
removal. However, it’s important to remember that filters with a higher
MERV rating must be replaced at least every three months to avoid restricted
air flow and negative effects on your furnace’s performance.
Changing your filters regularly and using the most efficient filter possible
for your furnace is the best way to control the air quality in your home
and maximize the lifetime of your heating and cooling unit. A little research
into MERV ratings will certainly pay off – in better health and improved
appliance efficiency.