A heating, ventilation and cooling (HVAC) air filter is your first line of defense against airborne pollutants. Even if regularly vacuum and clean your home, there are probably airborne pollutants floating around inside of it. Fortunately, the air filter will remove them. As air travels through your HVAC system, it will pass through the air filter. While all air filters are designed to remove airborne pollutants, however, they are available in several types.
The most common type, fiberglass air filters are characterized by the use of fiberglass. They typically have a Minimum Efficiency Reporting Value (MERV) rating of about 3 or 4. Regardless, all fiberglass air filters are made of glass- or plastic-reinforced fiber. This fiberglass material will catch particulate matter so that it doesn’t enter your home’s living spaces.
Pleated air filters are characterized by a pleated design. They aren’t made of fiberglass. Rather, pleated air filters are made of various organic or synthetic materials, some of the most common being cotton, polyester and paper.
While they usually cost more than fiberglass air filters, pleated air filters are more effective at removing airborne pollutants. Pleated air filters made of a synthetic material like polyester often have a MERV rating of about 8 to 10.
There are also non-pleated air filters. Any type of air filter that doesn’t have a pleated design is considered non-pleated. Fiberglass air filters, for example, have a flat design. They don’t contain grooves or pleats, so they are considered non-pleated air filters.
Some air filters are reusable. Also known as washable air filters, they’ve become a popular alternative to traditional and disposable air filters. With a washable air filter, you won’t have to constantly spend money replacing it. You can wash it every few months to keep it clean. Just remember to let your reusable air filter dry before reinstalling it. Installing a wet or damp air filter in your HVAC system may contribute to mold.
High-efficiency particulate absorbing (HEPA) air filters are those that are rated to filter at least 99.97% — or 99.95% in the United Kingdom – of pollutants measuring 0.3 micrometers or smaller. They are usually made of either fiberglass or polypropylene. These materials are arranged in small fibers that are able to trap exceptionally small pollutants. Some HEPA air filters, in fact, have a MERV rating of 15 to 20, making them superior to other types of air filters.