Image courtesy of NREL.

The recent publication of Standard 90.1-2016 marks the latest edition of the Standard, setting the stage for future building energy efficiency requirements in commercial buildings. ANSI/ASHRAE/IES Standard 90.1, known as the Energy Standard for Buildings Except Low-Rise Residential Buildings, is a model standard, developed jointly by ASHRAE and the Illuminating Engineering Society of North America (IES). An updated edition is published every three years and provides the basis for energy codes adopted by U.S. states. The 2016 edition contains several important changes to reduce energy consumption that will be of interest to the commercial building design and construction community.

What’s New in 90.1-2016?

Standard 90.1-2016 contains 121 new addenda (since publication of the previous 2013 standard). The new edition includes a new compliance path and a significant change in formatting, intended to improve its overall flexibility and use. A range of technical changes are also included, affecting building envelope, mechanical and lighting systems.

New Compliance Option: Performance Rating Method

The 2016 edition contains a new compliance path, known as the Performance Rating Method, which is included in Appendix G.

  • Appendix G now can be used as a path for compliance. (Previously it was used only to rate “beyond code” performance of buildings.)
  • It now serves as an alternative to the traditional performance path (Chapter 11: Energy Cost Budget), and creates a singular path to demonstrate both minimum code compliance and above-code performance.
  • A new metric, the Performance Cost Index (PCI), accommodates various climate zones and prominent commercial buildings types.
  • Appendix G baseline is now fixed at a specific level of performance, which is not expected to change with subsequent editions of the Standard, and will allow a building of any era to be rated using a single method.

New Climate Zones

Standard 90.1-2016 references the new ASHRAE Standard 169, Climate Data for Building Design Standards, providing an improved source for climatic data—now and into the future. 

  • Two new weather zones are added (climate zone 0 A and B), along with corresponding prescriptive requirements.
  • More than 400 counties (out of 3,000 across the U.S.) were reassigned and remapped based on updated weather data.
  • A new annex is appended and contains extracts from various reference standards for the convenience of users, including tables and figures extracted from Standard 169-2013.

A New Format

The Standard is now based on a new format for easier reading and use.

  • Requirements are now arranged in a one-column format.
  • Exceptions are separated, indented and in a smaller font size.
  • All defined terms are italicized.
  • An alternating color scheme has been applied to distinguish table rows.

New Technical Requirements

The most significant technical changes are summarized by building system:


  • Mandatory requirements for envelope verification, supporting reduced air infiltration, and increased requirements for air leakage to overhead coiling doors.
  • More stringent prescriptive requirements for metal building roofs and walls, fenestration, and opaque doors. 
  • Improved clarity of exterior walls definitions, building orientation, and clarity around the effective R-value of air spaces.
  • New requirements based on the addition of climate zone 0.


  • Modified control requirements to simplify advanced lighting control applications.
  • New exterior and interior lighting power densities based on LED technology.
  • Requirements for dwelling units to set limits on light source efficacy.
  • Additional controls for lighting in parking areas.


  • Chilled water plant metering, requiring large electric driven chilled water plants to be monitored for electric energy use and efficiency.
  • DOAS requirements, adding efficiency and rating requirements for dedicated outside air systems.
  • Elevator efficiency, introducing requirements for identifying usage category and efficiency class.
  • Economizer fault detection and diagnostics, implementing monitoring system requirements for air-cooled DX cooling units with economizers, helping to ensure that equipment is working properly.
  • New requirements for replacement equipment, such as adding economizers or fan speed control, which previously only applied to new installations.

What’s Next?

The new Standard 90.1-2016 is now available. Engineers, architects, and others involved in the design and construction of commercial buildings can immediately make use of the Standard. States will also begin reviewing the new edition as they work to update their commercial building codes.

Following the publication of a new edition of Standard 90.1, the U.S. Department of Energy (DOE) is required to review the updated code and issue guidance as to whether it will increase energy savings in commercial buildings. This helps set the stage for future code adoption by U.S. states and localities. DOE provides an array of technical assistance supporting adoption, including technical analysis of energy and cost savings, national and state-level impacts of new codes, and resources to improve implementation. DOE also tracks state code adoption and reports current status

More information on code adoption and related technical assistance is available at