DOE Reviews ASHRAE 90.1 to Evaluate Energy Performance

The U.S. Department of Energy (DOE) has released its Preliminary Energy Savings Analysis of ANSI/ASHRAE/IES Standard 90.1-2019, and is currently accepting written comments from interested parties on any subject within the scope of the analysis. According to the Energy Conservation and Production Act, as amended (ECPA), the DOE is required to review consensus-based building energy conservation standards, such as ASHRAE 90.1. Specifically, the ECPA provides that whenever the ANSI/ASHRAE/IESNA Standard 90.1-1989, or any successor to that code, is revised, the Secretary of Energy must determine whether the revised code would improve energy efficiency in commercial buildings and must publish notice of the determination in the Federal Register.

Standard 90.1-2019, published in October 2019, is the most recent addition, triggering the DOE review process. According to the DOE’s notice, ASHRAE has an established program for regular publication of addenda, or revisions, including procedures for timely, documented, consensus action on requested changes to the standard.

Also noted in the DOE’s notice, under President Biden’s executive order, “Protecting Public Health and the Environment and Restoring Science to Tackle the Climate Crisis,” the DOE was directed to “consider publishing for notice and comment a proposed rule suspending, revising, or rescinding the final technical determination regarding the ASHRAE Standard 90.1-2016 by May 2021.” As a result, the DOE is conducting its preliminary analysis of Standard 90.1-2019 so that its determination under section 304(b) of ECPA reflects the most recent version of Standard 90.1, and facilitates “State and local adoption of the Standard, which will improve energy efficiency in the nation’s commercial buildings.”

The DOE conducted a preliminary analysis to quantify the expected national energy savings associated with Standard 90.1-2019 relative to the previous 2016 version to meet the statutory requirement. The study determined that the 2019 edition of the ANSI/ASHRAE/IES Standard 90.1 would improve overall energy efficiency in buildings subject to the code (compared to the 2016 edition of Standard 90.1).

According to the preliminary analysis, the creation of Standard 90.1-2019 resulted in ASHRAE having published 88 addenda in total. Of these addenda, 29 are expected to decrease energy use (i.e., increased energy savings) and 59 are expected to have no direct impact on energy savings (such as administrative or clarifications or changes to alternative compliance paths). None are expected to increase energy use.

New commercial buildings meeting the requirements of Standard 90.1-2019 analyzed in the quantitative analysis resulted in national savings compared to Standard 90.1-2016. These results showed: 4.7% site energy savings, 4.3% source energy savings, 4.3% energy cost savings and 4.2% carbon emissions.

Addendum aw, which analyses fenestration U-factor and solar heat gain coefficient (SHGC), modified the vertical fenestration categories to “Fixed,” “Operable,” and “Entrance Door.” This revision is meant to ensure consistency with the International Energy Conservation Code (IECC). According to the addition, the revised SHGC values for operable and vertical fenestrations are slightly lower than those for fixed ones. According to the DOE analysis, this shows that operable windows have a larger frame-to-glass ratio and lower SHGC values with the same glazing type, adding that the addendum generally reduces U-factor for fixed metal-framed windows. However, it also increases the U-factor for non-metal framed windows.

The analysis also notes that since commercial construction mostly uses metal in framing, the average U-factor is reduced, lowering heat loss and gains for commercial buildings, which reduces both annual and peak heating and cooling loads. SHGC is slightly lowered overall, contributing further to a reduction in cooling load and energy use, reads the analysis.

According to the notice issued by the DOE, states can experience significant benefits by updating their codes to reflect current construction standards—a total estimated $51.59 billion in energy cost savings and 405.51 MMT of avoided CO₂ emissions in commercial buildings (cumulative 2010 through 2040), or $2.24 billion in annual energy cost savings and 17.57 MMT in annual avoided CO2 emissions (annually by 2030).

For additional information on the DOE analysis or to submit comments visit the Federal Register’s website.  Comments must be received by May 21.