The air filter is a vital component of your home’s HVAC system. It filters out contaminants to keep your indoor air fresh and clean and also protects the heating and air conditioning equipment from dust and dirt that could shorten its life. For maximum benefit, homeowners need to change the air filter every one to two months — more often if you have pets or a household member who suffers from environmental allergies. However, you have many choices when it comes to choosing an air filter. Here’s a guide to picking the perfect one for your home.
MERV Ratings
Image via Flickr by aaron_anderer
The most important factor when selecting your filter is the Minimum Efficiency Reporting Value, or MERV, rating. It’s a scale of one to 16, although there are higher-rated filters for specific industrial uses. The higher the rating, the more contaminants it will remove from the air. For example, a filter with a MERV rating of one to four will catch insects, dust, and some pollen. Filters rated five through eight capture fine household dust, pollen, pet fur, and mold spores. Filters rated nine through 12 can remove exhaust fumes, some bacteria, and even remove odors. Filters with a MERV rating of 13 through 16 remove bacteria, tobacco smoke, and some viruses.
Does this mean you should get the highest-rated filter on the market? Probably not. As you might expect, the cost of air filters increases along with the MERV rating. Also, your HVAC system may not be compatible with higher-rated filters. The higher the rating, the harder it is to pull air through it, which means your equipment will be working harder. The wrong air filter could shorten the HVAC system’s life or cause it to stop working entirely.
Spun Fiberglass Filter
Filters made from spun fiberglass encased in a cardboard frame are the least expensive filters you can purchase. They are usually rated one to four MERV, and are a good choice for people who don’t have allergies, asthma or pets that shed.
Pleated Paper Filter
Manufactured of paper, or sometimes polyester, that is pleated accordion-style, these filters are typically rated five to eight MERV. They are also relatively inexpensive and a common choice for most home HVAC systems.
Electrostatic Filters
Electrostatic filters work by attracting contaminants with electrically charged fibers. They are not, however, connected to any power source. These filters are available in a range of MERV ratings, typically from two to 10.
High MERV Pleated Filters
Filters with ratings of 13 and higher will filter out extremely small contaminants. They are also referred to as HEPA filters, and should only be installed in compatible HVAC systems.
Reusable Filters
Homeowners who want to save money or live in a more eco-conscious manner may choose reusable air filters. They are available in a wide range of MERV rating levels, and like any other filter, the cost varies as well. Although the initial expense will be much higher than the cost of disposable filters, they can last up to eight years.
Your choice of air filter for your home depends on your environment, your budget, and the HVAC system itself. If you’re still not sure which filter is best for your needs, contact a reputable HVAC service technician.
