ACCA Releases Residential Zoning Design Requirements

April 16, 2018

The Air Conditioning Contractors of America Educational Institute Standards Task Team announces the release of the revised ANSI/ACCA 11 Manual Zr – 2018 (Residential Zoning).

Manual Zr defines the requirements for designing zoned comfort systems for residential buildings, including single family detached and multifamily attached structures. Multifamily attached structures include duplexes, triplexes, town houses, row houses and small to medium size condominiums of three stories or less. Manual Zr also covers large multifamily, multi-floor buildings with dwellings that have their own comfort system, exhaust system, and outdoor air system.

“ACCA created Manual Zr because professional contractors recognized the need for an industry standard detailing how to handle excess air in dampered systems,” said John Sedine, chairman of ACCA Manual Zr Advisory Committee and president of Engineered Heating and Cooling of Cedar Springs, MI. “Excess air in zoned systems harms equipment, causes uneven building temperatures, and creates unhappy customers. Following the guidelines in Manual Zr helps contractors work through these problems and provides workable solutions to excess air, which is certain to satisfy their customers.”

Zoning can be provided by zone dampers in a duct system or by ductless multi-split equipment. It can also be done by two, or more, pieces of ductless split equipment, two or more central air systems, two or more PTAC or PTHP units, or by two, or more, AHAM units (air conditioner or heat pump). Zone valves in a hot water heating system (baseboard, or radiant panel) are also included in Manual Zr.

Manual Zr is available at

For more information, please contact ACCA’s Director of Industry and External Relations, Todd Washam, at or 703-824-8864.


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ACCA is a non-profit association serving more than 60,000 professionals and 4,000 businesses in the indoor environment and energy services community. Our member firms are the nation's most professional contracting businesses, serving residential and commercial customers in every state. With roots stretching back a century, ACCA was incorporated in its present form nearly 50 years ago. Today, ACCA sets the standards for quality comfort systems, provides leading-edge education for contractors and their employees, and fights for the interests of professional contractors throughout the nation. Learn more about ACCA here.