ANSI/ASHRAE/IESNA Standard 90.1-2004

DOE has issued a determination that the ASHRAE/IESNA Standard 90.1-2004 would achieve greater energy efficiency in buildings subject to the code, than the 1999 edition (Standard 90.1-1999 or the 1999 edition). The quantitative analysis of the energy consumption of buildings built to Standard 90.1-2004, as compared with buildings built to Standard 90.1-1999, indicates national source energy savings of approximately 13.9 percent of commercial building energy consumption. This process was completed and signed on December 30, 2008. View the complete determination notice that appeared in the Federal Register on December 30, 2008. (PDF 75 KB).

State Certification

Certifications or Requests for Extension of Deadlines, with regard to Standard 90.1-2004, will be due to DOE 2 years after DOE formally issues its determination of energy savings for Standard 90.10-2004 (December 12, 2010).

As required by the Act, all states have two years to adopt Standard 90.1-2004 or upgrade their existing commercial building codes to meet or exceed its requirements.

Quantitative Analysis

A quantitative analysis of the estimated differences between the 1999 and 2004 editions (including changes made to the 2001 edition) of Standard 90.1 has been performed to inform and support the final determination. An Excel spreadsheet containing the analysis can be downloaded at no cost (ZIP 3.4 MB).

An Explanation of the Analysis and Spreadsheet is available to assist in understanding the analysis.

Detailed Textual Analysis

A Detailed Textual Analysis of the estimated differences between the 1999 and 2004 editions of Standard 90.1 has been performed to inform and support the final determination (PDF 128 KB).