ASHRAE Standard 90.1

The purpose of this ASHRAE standard is to establish the minimum energy efficiency requirements of building design and construction, other than low-rise residential buildings.

Read more about the International Energy Conservation Code (IECC), the standard that covers low-rise residential construction.

ASHRAE Standard 90.1

Standard 90.1 has been a benchmark for commercial building energy codes in the United States and a key basis for codes and standards around the world for more than 35 years. This standard provides the minimum requirements for the energy efficient design of most buildings and offers, in detail, the minimum energy efficient requirements for the design and construction of new buildings and their systems, new portions of buildings and their systems, and new systems and equipment in existing buildings as well as the criteria for determining compliance with these requirements. It is an indispensable reference for engineers and other professionals involved in the design of buildings and building systems.

ANSI/ASHRAE/IES Standard 90.1-2016, the tenth edition, is now available. The goal of this version, like those before it, is to “create a consensus standard that saves energy and is technically feasible and cost effective”, according to Drake Erbe, the chair of the Standard 90.1 committee. Noteworthy changes include the addition of an envelope verification requirement and prescriptive guidelines for Climate Zone 0. Appendix G, previously used only to rate “beyond code” performance, can now be used as a path for compliance.

Read the press release from ASHRAE.

What You Need to Know about the New Energy Standard for Commercial Buildings: Standard 90.1-2016 (webinar)

In early 2016, ASHRAE unveiled a new web application designed to automate Energy Cost Budget (ECB) calculations needed to show compliance with Standard 90.1-2010. Several states currently use this standard as a commercial energy code, including Florida, Iowa, New York, and Virginia.
Article: New ASHRAE Application Automates Compliance Calculations for Standard 90.1-2010 (January 23, 2016)

The revised standalone appendix for using Appendix G to show code compliance is available for purchase now in advance of the full code publication for those who wish to get ahead of the curve.


The following states have adopted ASHRAE 90.1 directly (i.e. not as a compliance path through the IECC): Alabama, Indiana, Louisiana, Mississippi, New Jersey, Oregon*, West Virginia.

*state-developed commercial code is based on ASHRAE 90.1-2010


Changes made to ANSI/ASHRAE/IES Standard 90.1-2013 include:

  • Revised, stricter opaque element and fenestration requirements at a reasonable level of cost-effectiveness
  • Improvements to daylighting controls, space-by-space lighting power density limits, and thresholds for toplighting
  • Revised equipment efficiencies for heat pumps, packaged terminal air conditioners (PTACs), single package vertical heat pumps and air conditioners (SPVHP and SPVAC), and evaporative condensers
  • New provisions for commercial refrigeration equipment and improved controls for heat rejection and boiler equipment
  • Improved requirements for expanded use of energy recovery, small-motor efficiencies, and fan power control and credits
  • Improved equipment efficiencies for chillers
  • Clarifications for the use of prescriptive provisions when performing building energy use modeling, and revisions to enhance capturing daylighting when performing modeling calculations
  • A new alternate compliance path to Section 6, “Heating, Ventilating, and Air-Conditioning,” for computer room systems, developed with ASHRAE Technical Committee (TC) 9.9

Resources