ANSI/ASHRAE/IES STANDARD 90.1-2016 – Energy Standard for Buildings

***Update: This standard has been revised. ANSI/ASHRAE/IES 90.1-2019: Energy Standard For Buildings Except Low-Rise Residential Buildings is available on the ANSI Webstore. You can also learn about the numerous changes made to the revision here: ANSI/ASHRAE/IES 90.1-2019: Energy Standard For Buildings.


ANSI/ASHRAE/IES STANDARD 90.1-2016 – Energy Standard for Buildings Except Low-Rise Residential Buildings (I-P Edition) covers minimum energy efficiency requirements for the construction, design, and maintenance of buildings.

It applies specifically to new buildings, or new portions of buildings, and their systems, along with new systems and equipment in existing buildings and new equipment or building systems specifically identified in the standard that are part of industrial or manufacturing processes.

Maintaining energy efficiency in commercial and residential buildings is beneficial to everyone, regardless of their unique stakes. Currently, residential or commercial buildings use up about 40 percent of the total U.S. energy consumption. This equates to 39 quadrillion British thermal units.

Minimizing this usage through appropriate building insulation is advantageous for both the users of that energy, since they cut costs, and the environment, as the reduction in energy consumption limits the amount of fossil fuels used. In this way, ANSI/ASHRAE/IES STANDARD 90.1-2016 fulfills the duty of modern standardization efforts by thinking both economically and environmentally.


ANSI/ASHRAE/IES STANDARD 90.1-2016 accomplishes this by identifying the different ways in which buildings are constructed to be more energy efficient. In general, this covers many provisions relating to insulation, windows, and doors, so that the building envelope, the “the exterior plus the semiexterior portions of a building”, is designed and constructed with a continuous air barrier, “the combination of interconnected materials, assemblies, and sealed joints and components of the building envelope that minimize air leakage into or out of the building envelope”.

Furthermore, the standard details specifications for different opaque elements commonly found in buildings, addressing ways in which they limit air leakage. The methods of determining this as a whole can be complicated, but ANSI/ASHRAE/IES STANDARD 90.1-2016 addresses different formulas for calculating such values.

As a fluid document, ANSI/ASHRAE/IES STANDARD 90.1-2016 is updated approximately every 3 years, and this latest revision marks several changes. Since the particular compliance path for energy efficiency varies between different buildings, the extensive document has undergone several formatting changes to improve usability and, in turn, compliance.

These changes include a one-column format, italicized defined terms, table format alterations to provide contrast between rows, and a clear separation, through indentions and a smaller font , of exceptions mentioned for particular specifications in the document.


There have also been modifications made to the technical provisions of ANSI/ASHRAE/IES STANDARD 90.1-2016. These relate to building envelopes (addition of verification in support of reduced air filtration and increased stringency for metal building roof and walls), lighting (recognizing LED as a common application of current lighting design), mechanical requirements (addition of chilled-water plant metering and elevator efficiency), and energy cost budget (ECB) and modeling (changes to Appendix G).

As explicitly noted by its title, ANSI/ASHRAE/IES STANDARD 90.1-2016 does not apply to single-family houses, multifamily structures of three stories or fewer above grade, manufactured houses (mobile homes), manufactured houses (modular), or buildings that use neither electricity nor fossil fuel.

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