ATLANTA — Public input is being sought on revisions to ANSI/ASHRAE/IESNA Standard 100-2006, Energy Conservation in Existing Buildings. Last year, the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) and the Illuminating Engineering Society of North America (IESNA) announced they were revising Standard 100-2006 to provide greater guidance and a more comprehensive approach to the retrofit of existing buildings for increased energy efficiency. The standard was first published in 1981, and the associations noted that the need for its requirements has grown as more attention is paid to improving efficiency in the current building stock.

“Information from the International Energy Agency shows that the building sector is the largest consumer of energy in the United States, using some 40.3 quadrillion Btus of energy in 2002, around 41 percent of total U.S. energy use,” said Rick Hermans, chair of the committee writing the standard. “Compliance with this standard by every building would reduce that energy use by three quarters.”

The proposed changes include criteria for energy use surveys and auditing and requirements related to implementation and verification. Appendices are included for life cycle cost analysis procedures as well as identification of potential energy conservation measures.

Recognizing that the actual occupancy of the building plays a key role in its performance, the standard established the need for development of an energy management plan and an operation and maintenance plan.

“The standard takes advantage of the fact that any building which has been in operation for at least 12 months can quickly determine its performance relative to some benchmark, which is defined in the standard as an energy use intensity target,” said Hermans. “This concept is the new paradigm for energy conscious design, construction, and operation of buildings.”

The standard provides requirements for the retrofit of existing buildings and addresses major and minor modifications for both residential and commercial buildings, single and multiple activity buildings with variable occupancy periods, and identifies an approach for 53 building types in 16 climate zones/sub-zones.

The revised standard also identifies energy efficiency requirements for buildings with and without energy targets and provides multiple levels of compliance.

Public comment on the proposed changes is being sought until June 18. For more information on the changes and how to comment, visit

Publication date: 05/21/2012