The Best Types of Filters for a Central-Air System

HEPA Filters

• High-energy particular air, or HEPA, filters capture 99.97 percent of airborne particles size 0.3 microns and larger, according to allergy and air products website, Achoo Allergy. These filters are ideal for capturing pollen, dust-mite proteins and mold that enter central-air systems from outside the home. HEPA filters can also reduce the amount of pet dander in the home, which is especially important if anyone living there is allergic to pets. According to the Environmental Protection Agency, some residential central-air systems do not have the motor capacity to support these high-efficiency filters, so check with the central-air system manufacturer to find out if a HEPA filter is safe for your system.

Activated-Carbon Filters

• Activated-carbon filters can remove gases, odors and toxins, such as volatile organic compounds found in most household cleaners, from your air supply. These filters use oxygen-treated carbon or activated-charcoal to create a porous surface that effectively traps particles moving through it. This is particularly useful if you do a lot of home cooking and don't want the smell of garlic or other cooking smells carried through your entire home by the central-air system.

Electrostatic Filters

• Electrostatic filters are composed of fibers that use static-electric charges to trap particles that attempt to pass through them. These filters never have to be replaced and only require regular cleaning to keep them functional. There is a danger with these filters, as some emit ground-level ozone that can cause lung irritation and aggravate asthma conditions. Avoid using electrostatic filters that emit ground-level ozone.

Charged-Media Filters

• Charged-media filters use electrostatic energy but are made from synthetic fibers and charged through the manufacturing process. According to Achoo Allergy, these filters operate with a high degree of energy efficiency and do not restrict air flow as much as other air filters. The filter does begin to restrict air flow when it becomes too clogged with airborne particulates and must be regularly changed to maintain optimal performance. Charge-media filters are able to catch allergen causing particles as well as bacteria, which HEPA filters cannot.