How to Choose an Air Filter System for the Home

Select one of the primary types of home air filter systems: High Efficiency Particulate Air (HEPA) or Ionic. HEPA filters filter the smallest particles including dust, smoke, and a variety of allergens like pollen. Ionic filters electrify the filter and attract allergens, so they can filter out equally small particles.

Select between a whole-house air-filter system or a portable home air-filter system by deciding if you need to or can afford to filter the entire house. Whole air-filter systems work much like central air-conditioning and filter the air system via a system of vents and filters. Portable home air-filter systems consist of stand-alone units capable of filtering one or two rooms.

Match the air filter's clean-air delivery rate (CADR) with the size of your home by selecting a filter capable of filtering two-thirds of your room's overall square footage (sf). If your room measures 300 sf, look for filter with a 200 CADR. The CADR indicates how much square foot of clean air a filtering system can deliver, and you need a filter with a 100 to 300 CDR.

Compare filter shape, and look for systems that use a creased 'W' filter. Creased filters double (sometimes triple) a filter's surface area, so it can filter more pollutants without needing replacement.

Compare price. Whole-home filter systems cost between $700 and $3,000 while portable ionic or HEPA filter systems cost $69 to $300. Individual replacement filters for both whole-home systems cost $10 to $35 per filter while replacement filters for portable units cost $6 to $35 per filter.