What is MERV?
MERV is the rating scale used to determine how effective a furnace filter is at capturing pollutants, pet dander, dust particles and any other debris cycling through your home’s air. Minimum Efficiency Reporting Value was developed by the American Society of Heating, Refrigeration and Air Conditioner Engineers – ASHRAE. A MERV rating ranges anywhere from 1 to 16, the best being 16 and the least effecting being 1. The value of a MERV rating is dependent on the size of the holes in the filter, which depicts what size of particles can pass through it. Those filters with bigger holes get a smaller MERV rating and those with smaller holes, making the filter more effective, get a higher rating.
While it is important to choose the most efficient filter possible for the best indoor air quality in your home, it is also important to keep in mind that it is not always as easy as buying a filter with the highest MERV rating. Because the pore sizes are so small in these highly-rated MERV filters, the filter will cause more air resistance against air flow. If your furnace is not built for a high rated MERV filter, it will put too much pressure on the fan of your furnace or air conditioning unit which can lead to malfunction. It is important to chose an air filter with the highest MERV rating that your particular system will allow. Essential information about specific MERV ratings and suggestions for your system will be included with the documentation that came with your system when you bought it. If you are like most Americans who have since lost or misplaced this inforamtion; no worries. These manuals are easily searchable online.
Here is breakdown of the most common air filters and their MERV ratings:
- Throw-Away Fiberglass Media: MERV 1 – MERV 4
- Pleated Media Air Filters 30%: MERV 10 – MERV 11
- Pleated Media Air Filters 65%: MERV 13 * (* 65% ASHRAE is about 20% effective on particles less than 1 micron in size)
- Pleated Media Air Filters 95%: MERV 14
For most residential home’s furnace and air conditioning units we recommend choosing an air filter between the range of MERV 8-12. If your system can handle a filter with a higher rating, you may want to bump up to a MERV 13 to receive even better, cleaner air. However, keep in mind ** with a higher MERV rating you must replace the filter at least every 3 months to avoid the negative effects of restricted air flow discussed above. MERV 15 and 16 filters are typically used for Dr. Offices, those with allergies, asthma, respiratory problems or those very conscious of clean, healthy air!
Check out some of our most Popular Furnace Filters:
If you need any more information or have any questions as you consider an indoor air quality purchase, please do not hesitate to contact our customer support team via email by clicking here: I Have A MERV Question