ASHRAE is now accepting public comment on ANSI/ASHRAE/IESNA Standard 100-2006, Energy Conservation in Existing Buildings. The standard was first published in 1981. The public review process seeks suggestions for new, unusual, or potentially controversial elements of a proposed standard. The advisory public review is open until May 25, 2011 at

According to ASHRAE, of the 94.6 quadrillion Btu of energy consumed in the United States in 2009, 42 percent was used by commercial and residential buildings. Over the next 24 years, national electric consumption is expected to grow by over 22 percent, and natural gas consumption by 16 percent. In the same period, the amount of commercial and residential floor space in the marketplace is expected to increase by 37 percent and 17 percent respectively.

“In order to offset the growing amount of floor space and subsequent increased energy demands, existing buildings must improve their efficiency, even if every new square foot were built and operated at net zero energy,” says Rick Hermans, chair of the Standard 100 committee.

The revised standard provides comprehensive and detailed descriptions of the processes and procedures for the energy efficiency improvements of existing residential and commercial buildings in order to achieve greater energy efficiency. The standard addresses major and minor modifications for both residential and commercial buildings, single, and multiple activity buildings with variable occupancy periods, and identifies an energy target for 53 building types in 16 climate zones and sub-zones.

The revised standard also identifies energy efficiency requirements for buildings without energy targets--mostly industrial, agricultural, data centers and special laboratories--and provides multiple levels of compliance.

The standard establishes the requirement for developing an energy management plan and an operation and maintenance plan, according to Hermans. Also included within the revised standard is criteria for energy use surveys, auditing, implementation, and verification. Appendices are included for life cycle cost analysis procedures as well as identification of potential energy efficiency measures.

“Through this advisory public review, we are seeking broad and general comments on the text of the standard, the concepts of requirements and opinions about the value of the standard,” Hermans says. “Throughout the text there are questions seeking your advice as reviewers of this draft document. Please look at these questions and add your thoughts, answers and comments in the ASHRAE comments database as described in the instructions.”