MERV Rating is the 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 A piece of copy paper is about 100 microns. A human hair averages 80 microns in size. Pet dander is 2-4 microns and can linger in the air for hours before it settles uses the MERV Rating system. AC Furnace Air Filters are manufactured direct since 1960. We have all standard AC Furnace Air Filters and all custom sized AC Furnace Air Filters. In the average American home, the most common air filter is only a MERV 4.

These are usually the furnace filters that you can see through and do not stop particles smaller than 10 microns. systems are well able to use the 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 to grade their air filters based on the ability to filter air particles smallerThe microparticle performance rating is not considered to be the industry standard by the American Society of Heating, Refrigerating and Air ConditioningThe published MPR Rating numbering system is a scale of 0 – 2700, with their highest published furnace filter equaling the Nordic Pure MERV 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 always It’s important to note that the MERV Rating is the “MINIMUM” initial efficiencyIt’s the efficiency rating given to the air conditioner furnace filter when it is brand new and is expressed as a percentage of the total airborne particles of a certain size. As the new air conditioner furnace filter traps more debris, it becomes more efficient – trapping the smallest particles as time goes by. every air filter will trap the tiniest particles less than 1 micron, until it becomes so dirty that air cannot get through. Air Filter Gages measure the building pressure behind the aging furnace filter and can let you know it’s time for a AC FurnaceOur customers also benefit from our Free Reminder Service that will automatically notify you by email or phone that it’s time to check, change or replace your air conditioner furnace filters. Nordic Pure manufacture direct since 1960.

Multiple air filter media available:hvac unit fan not running MERV 7, MERV 7 Plus Carbon, MERV 8, MERV 8 Plus Carbon, MERV 10, MERV 10 Plus Carbon,how to clean mold from ac unit MERV 11, MERV 11 Plus Carbon, MERV 12, MERV 12 Plus Carbon, MERV 13, MERV 13 Plusac unit line freeze Carbon, MERV 14, MERV 14 Plus Carbon, MERV 15 and MERV 15 Plus Carbon. Nordic Pure AC Furnace Air Filters are available in ½ inch air filters, 1 inch air filters, 2 inch air filters, 4 inch air filters, 5 inch air filters, and 6 inchCustom size air filters are also available. Please call us at 1-800-590-0339. MERV, MPR, FPR, RATING ASHRAE MINIMUM INITIAL EFFICIENCY .30 to 1.0 Microns 1.0 to 3.0 Microns 3.0 - 10.0 Microns < 0.30 Micron carbon dust sea salt all combustion smoke Clean Room Manufacturing Electronics Manufacturing Pharmaceuticals Carcinogenic Materials Hospital Inpatient Care Surgery Superior Commercial Buildings MERV 17-18 (HEPA) N/A N/A > 95%

< 75% > 90% Textile / Carpet Fibers MERV 0 - MERV 5Updated Thomas here, from Smart Air. I was living in China and concerned about what the air was doing to my health, so I started building DIY Air Purifiers and doing air quality tests in China. When I was doing those tests, I encountered two problems that are relevant to your question:1. Do wall-mounted air conditioners bring in dirty outdoor air?The tubes on my air conditioner led outside, so I had always presumed they brought in outdoor air. But it turns out they don't push indoor air out or bring outdoor air inside. They just recycle air indoors.But to be doubly sure, I ran tests! I waited for bad air pollution days in Beijing. (I didn’t have to wait long.) Then I tracked air quality before and after I turned on my AC unit.On average, particle counts had no change or went slightly down. You can see a video test and more info here:Does Air Conditioning Bring in Dirty Outside Air?However, that test was for particulate, and the question mentioned carbon dioxide.

That brings up this question:2. Even with the doors and windows closed, how much outdoor air is getting into our homes?If a lot of outdoor air is getting in, then carbon dioxide build-up shouldn't be a problem. I tested this in Beijing by leaving a particle counter on in my apartment while I went away on vacation for several days. All the windows and doors were closed. I also left an air purifier on a timer to turn on for two hours every day. Here's what I found when I came back:It's shocking how quickly the air became dirty again. Why is it getting dirty so quickly? Because outdoor air is constantly getting in--even in this most conservative test. I wasn't even home opening doors or walking in from outside.More info on that test here:http://particlecounting.tumblr.c...A caveat: some houses are sealed better, some are sealed worse.Conclusion: If your main concern is carbon dioxide, I wouldn't worry about pushing air out. However, I would make two exceptions:Exception 1: If you have an abnormally high number of people in the room or a very good seal around windows and doors, carbon dioxide will build up more.