Air filters are a necessary component of your HVAC system, and changing them is a fairly simple task. However, what many homeowners find confusing is choosing the best ones to suit their needs, given the vast selection of products available today. Are pleated filters better than flat ones? And what do the efficiency ratings on the label mean?
MERV, which stands for Minimum Efficiency Reporting Value, is a rating system that classifies air filters according to their ability to capture particles from the air. Filters with higher MERV ratings can capture smaller particles than lower-rated ones, thereby removing more contaminants from the air. Here are the basics of what MERV ratings mean for your indoor air quality:
MERV 1 to 4 – Air filters in this range are usually disposable flat or panel types. They have a medium efficiency in capturing large airborne particles, such as dust, dust mites and pollen. While they’ll protect system components from dirt, they’ll do little or nothing to protect or improve indoor air quality.
MERV 5 to 8 – These may be panel-type filters or pleated ones, and are capable of trapping smaller particles, such as mold spores, dusting aids, cement dust and hair spray.
MERV 9 to 12 – Filters with these ratings trap fine particles, such as humidifier dust, auto emissions and lead dust.
MERV 13 to 16 – These filters are designed to capture very fine particles, such as tobacco smoke and bacteria.
MERV 17-20 – These are high-efficiency (HEPA) filters, trapping tiny particles, including viruses and all combustion smoke, typically used in hospital cleanrooms and industrial situations, though they are commonly used in stand-alone air purifiers intended for residential use and vacuum cleaners.
As you choose air filters, you should know that as the MERV rating rises, so does airflow restriction. For the average home HVAC system, filters in the 8 to 12 category are generally best, offering improved air quality without inhibiting airflow too drastically. However, before upgrading to higher-rated filters, be sure to double-check with your HVAC professional to ensure that your system can handle the change. Also, you may find out that a certain high-rated MERV filter won’t even fit in your HVAC equipment without serious system modifications.
If you still have questions on choosing the best air filters for your needs, please contact Ace Hardware Home Services, Inc. Family owned and operated, we’ve been serving homeowners in the Dayton area since 1979.
Our goal is to help educate our customers in Dayton, Ohio about energy and home comfort issues (specific to HVAC systems). For more information about air filters and other HVAC topics, download our free Home Comfort Resource guide.
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