By Christina B. Farnsworth. Central vacuum systems are among the best indoor air quality (IAQ) investments. Beam Industries recently introduced an affordable builder unit. A three-inlet system for a home as large as 2,400 square feet starts at $399. Turnkey with installation, the price is $729.

Central systems, unlike their ungainly upright and canister cousins (which the EPA finds capture only 15 percent of pollutant particles), have five times the suction to remove dust, dirt, and allergens into canisters located outside conditioned space.

The Division of Rheumatology, Allergy, and Clinical Immunology at the University of California-Davis School of Medicine surveyed the homes of 25 allergy patients. Each home used a conventional consumer vacuum for half of the survey time and a central vacuum system for the other half. Patients claimed various symptoms improved from 44 percent to 61 percent with use of a central vacuum.