ARLINGTON, Va. - The Air Conditioning Contractors of America (ACCA) has posted the last in a five-month series of technical reference bulletins on its Web site.

"Balancing Residential Air Distribution Systems" describes the characteristics of air and the physics of duct flow. The principles are discussed as background for the concept that the air side of residential comfort systems must be tested, adjusted, and balanced in order to avoid equipment failure and ensure the system delivers a full measure of comfort to homeowners.

The technical bulletin covers blowers and air-side devices, balancing instruments, and balancing procedures. It is available for ACCA members to download at

Publication date: 01/24/2005