When it comes to air filtration, a filter with a MERV rating of 10 to 12 is usually enough to remove most allergy-causing particles from your home. If you're looking for an air filter that can eliminate common allergens, look for one that has the words “allergy” or “allergen” on its packaging. The MERV rating you choose between 7 and 13 depends on the level of filtration you need. If your family suffers from allergies or asthma, then a higher MERV score is the way to go.
On the other hand, if your family doesn't have any respiratory issues, then a lower filter such as a 7 will save you money on your energy bill. These filters will have the least restriction to air flow and will trap the lowest volume of particles. The chart also uses percentages based on the chances of an air filter capturing dust particles based on micron size. Despite warnings, many people have reported that MERV 11, 12 and even 13 filters have worked well in their systems for years.
To get into more detail about the two, consider that MERV 11 filters trap 65 to 79 percent of the average particles 1.0 to 3.0 microns in size, with an average particle size efficiency of 85 percent or better. Additionally, a MERV 12 filter that is only 1 inch thick is likely to be more restrictive than a 4 inch thick MERV 12 filter. A filter with a MERV rating between 1 and 6 can remove particles between 0.3 and 10 microns with an efficiency of 20%. The air filter is designed to control the amount of unwanted air particles entering your home, and its MERV rating helps you determine which filter is best for your home.
If you can't find Nordic Pure in your size, or if you prefer to buy a new filter from a store immediately, Honeywell's FPR 9 filters and Filtrete MPR 1500 filters are similar and widely available in retail stores. Remember to replace the filter every month, three months, six months or year, depending on the filter.
