ANSI/ASHRAE/IES 90.1-2022: Energy Standard For Buildings

The energy standard for buildings has been revised: ANSI/ASHRAE/IES 90.1-2022: Energy Standard For Sites And Buildings Except Low-Rise Residential Buildings (I-P Edition).

The earliest human shelters guarded Paleolithic gatherers with basic protection from the elements and had few amenities. Today, things are quite different, as buildings comprise complex systems that provide occupants with comfortable, safe, and attractive living and working environments. However, this necessitates superior architecture and engineering designs and quality construction practices. In result, lighting, major appliances, electronics, and heating, ventilation, and air conditioning (HVAC) can consume a great deal of energy.

As noted by the U.S. Department of Energy (DOE), the buildings sector accounts for about 76% of electricity use and 40% of all U.S. primary energy use and associated greenhouse gas (GHG) emissions. To face energy and environmental challenges, it is crucial to reduce energy consumption in buildings. This also can lower costs to building owners and tenants.

What Does ASHRAE 90.1 Cover?

ANSI/ASHRAE/IES 90.1-2022 helps meet this need by offering minimum energy-efficient requirements for the design, construction, operation, and maintenance of buildings and sites and their utilization of on-site renewable energy resources. It applies to new buildings and new portions of buildings and their systems, new systems and equipment in existing buildings, new systems and equipment that are part of a site, and new equipment or building systems that are part of industrial or manufacturing processes. The standard also provides criteria for determining compliance with these specifications.

ANSI/ASHRAE/IES 90.1-2022 does not apply to single-family houses, multifamily structures of three stories or fewer above grade, manufactured houses (mobile homes), manufactured houses (modular), and buildings that use neither electricity nor fossil fuel.

ASHRAE 90.1 and Energy Conservation Regulation

Many in the United States know the ANSI/ASHRAE/IES 90.1 standard as one of the two baseline energy conservation codes adopted by regulatory authorities throughout the nation. The other is the International Energy Conservation Code (ICC IECC). The IECC, ASHRAE 90.1, or a combination of both are adopted by almost all states. You can see a list of all state building energy code adoptions here.

Both baseline energy conservation codes are available together as the ICC IECC / ANSI/ASHRAE/IES 90.1 – Energy Conservation Set.

Changes to ANSI/ASHRAE/IEC 90.1-2022

ANSI/ASHRAE/IES 90.1-2022 revises the 2019 edition of the same American National Standard, which was titled, “Energy Standard For Buildings Except Low-Rise Residential Buildings.” It incorporates more than 80 addenda to the 2019 edition and includes numerous energy-saving measures. Changes to the new standard include:

• The scope of the standard has been expanded to include not only buildings but sites, enabling regulation of energy use associated with the building but not in the building itself, such as parking lot lighting not connected to the building service or photovoltaic equipment located on site but not within the building. This change is reflected in the update to the title of the standard.
• New Section 11, “Additional Efficiency Requirements,” was added. It enables approximately 4% to 5% cost-effective energy savings through 33 different energy-saving measures.
• A minimum prescriptive requirement for on-site renewable energy was added.
• A requirement was added to perform whole-building air-leakage testing and measurement on buildings less than 25,000 ft².
• Requirements were added that address the impacts of thermal bridges in building envelopes.
• New Informative Appendix K, “Informative Figures—Thermal Bridges,” was added.
• Solar reflectance requirement for walls was added for Climate Zone 0.
• Specific provisions were added to distinguish roof replacements from other types of alterations.
• A new reference was added for steel-framed walls to allow use of ANSI/AISI S250 for U-factor determination.
• Added a definition for insulated metal panels (IMPs).
• New Normative Appendix A, “Rated R-Value of Insulation and Assembly U-Factor, C-Factor, and F-Factor Determinations,” was added.
• Updated installed interior lighting power allowances and minimum control requirements.
• Added a power exception for the germicidal function in luminaires and sources.
• Removed exceptions for casinos and parking garage daylight transition zone lighting.
• Modified a number of lighting requirements to reflect greater use of higher efficiency LED products and revised lighting practices.
• Added requirements for indoor horticultural lighting in greenhouses and indoor grow buildings based on a new metric, photosynthetic photon efficacy (PPE), developed in ANSI/ASABE S640.
• Provided an additional interior lighting power allowance for video conferencing.
• Introduced an optional Mechanical System Performance Path that allows HVAC system efficiency tradeoffs based on a new metric, total system performance ratio (TSPR).
• Required condensing boilers for new construction in order to achieve 90% or greater efficiency for large boilers.
• Established a minimum enthalpy recovery ratio for energy recovery systems and specified operational requirements to ensure proper economized performance.
• Revised demand control ventilation requirements to be based on climate zone and ANSI/ASHRAE 62.1 airflow requirements.
• Modified the minimum efficiency requirements for air-source heat pumps and introduced a new metric, COP_HR, for units that perform heat recovery during chiller operation.
• Added the minimum energy efficiency requirements (and new CFEI metric) for large-diameter ceiling
• fans from 10 CFR 430.
• New requirements were added to Normative Appendix G, “Performance Rating Method,” to limit trade-offs between the building envelope and other building systems.
• New Informative Appendix I, “Using Other Metrics in Conjunction with Appendix G Performance Rating Method when Approved by the Rating Authority,” was added.
• New Normative Appendix J, “Sets of Performance Curves,” was added.

ANSI/ASHRAE/IES 90.1-2022: Energy Standard For Sites And Buildings Except Low-Rise Residential Buildings is available on the ANSI Webstore.

Energy Standard for Low-Rise Residential Buildings

Users should note that there is an exception to this standard noted explicitly in its title: low-rise residential buildings. The purpose of ANSI/ASHRAE/IES 90.1-2022 is:

“To establish the minimum energy efficiency requirements of buildings other than low-rise residential buildings.”

Low-rise residential buildings are defined here as:

“single-family houses, multifamily structures of three stories or fewer above grade, manufactured houses (mobile homes), and manufactured houses (modular).”

Energy efficiency guidelines for these buildings are specified in a separate document, ANSI/ASHRAE/IES 90.2-2018: Energy-Efficient Design Of Low-Rise Residential Buildings, which is also available on the ANSI Webstore.

If you’d like to learn more about this standard, please refer to our post ANSI/ASHRAE 90.2-2018: Energy-Efficient Design Of Low-Rise Residential Buildings.

Changes to ANSI/ASHRAE/IES 90.1-2019

ANSI/ASHRAE/IES 90.1-2019 revised the 2016 edition of the same American National Standard. While it is now superseded by the current edition of the standard, it was a sizable revision. In all, it incorporated over 100 addenda to the 2016 edition, as well as numerous energy-saving measures. Changes were made to various areas throughout, including administration and enforcement, the building envelope, lighting, mechanical, energy cost budget (ECB), the performance rating method, and compliance paths.

Notable changes to ANSI/ASHRAE/IES 90.1-2019 include:

• “Commissioning requirements” were added to the standard.
• Substantial expansions to section 4.2.5, “Verification, Testing, and Commissioning.”
• New Informative Appendix H, “Additional Guidance for Verification, Testing, and Commissioning.”
• The categories of “nonmetal framed” and “metal framed” products were combined for vertical fenestration.
• Minimum criteria for solar heat gain coefficient (SHGC) and U-factor were upgraded across all climate zones.
• The air leakage section was revised to clarify compliance.
• In the vestibule section, the standard refined exceptions and added a new option for using air curtains.
• To reflect the outcomes of the fully reconstructed ANSI/ASHRAE Standard 90.1 lighting model, lighting power allowances for the Space-by-Space Method and the Building Area Method were modified. As mentioned in the standard, this model is “more representative of real-world conditions with the inclusion of updated IES recommendations, room cavity ratios, additional surface reflectance categories, light loss factors, and a 100% LED technology baseline with updated efficacy values.”
• New section 9.2, “Compliance Paths,” was added to cover a simple approach for designers who design or renovate office and retail buildings up to 25,000 ft².
• Lighting control information for parking garages were updated to account for the use of LED. The new edition increases “the stringency of the setback requirement to 50%” and reduces “the control timeout from 20 minutes to 10 minutes.”
• Daylight responsive information was updated from continuous dimming or stepped control to continuous dimming for all spaces.
• New definition added for continuous dimming based on NEMA LSD-64-2014.
• Side-lighting guidance was updated to clarify that the setback distance is a horizontal measurement, and the exception was amended to include natural objects as an obstruction.
• Designers were given the option to use ANSI/ASHRAE 90.4 instead of ANSI/ASHRAE 90.1 in computer rooms that have an IT equipment load larger than 10 kW.
• Pump definitions, requirements, and efficiency tables are included in the standard.
• Table F-4, “Residential Furnaces—Minimum Efficiency Requirements for U.S. Applications (see 10 CFR 430),” and Table F-5, “Residential Boiler Minimum Efficiency Requirements for U.S. Applications (see 10 CFR 430),” were created for U.S. federally covered furnace products and to specify USDOE-covered residential water boiler efficiency requirements.
• The efficiency table for liquid-to-liquid heat exchangers was removed.
• Table 6.8.9-17, “Ceiling-Mounted Computer-Room Air Conditioners—Minimum Efficiency Requirements,” was added.
• Table 6.8.1-16, “Heat-Pump and Heat Recovery Chiller Packages—Minimum Efficiency Requirements,” was added, along with new guidance for heat pump and heat reclaim chillers.
• New information for vacuum insulating glazing was added to the list of options for section 6.4.5, “Walk-In Coolers and Walk-In Freezers.”
• The fan efficiency grade (FEG) efficiency metric was replaced with fan energy index (FEI).
• Section 6.5.3.1.2, “Fan Motor Selection,” was updated to increase design options for load-matching variable-speed fan applications.
• Section 6.4.1.3, “Ceiling Fans,” added new information for reporting fan power.
• Energy recovery information was included for high-rise residential buildings.
• New information was added for condenser heat recovery for acute care inpatient hospitals.
• The baseline was set for on-site electricity generation systems in section 11, “Energy Cost Budget Method.”
• Rules in Normative Appendix G, “Performance Rating Method,” were clarified when combining multiple thermal zones into a single thermal block.
• Explicit heating and cooling coefficients of performance (COPs) were provided without fan for baseline packaged cooling equipment.
• Rules were added for modeling the impact of automatic receptacle controls.
• More specific baseline rules were set for infiltration modeling.
• Clarification was added on performing plant and coil sizing.
• Building performance factors were updated.
• Clearer rules were added to how renewables are treated.
• Numerous updates were added to the rules for lighting modeling.

Changes to ANSI/ASHRAE/IES Standard 90.1-2016

While not as significant of a revision as the 2018 and 2022 editions and now superseded by the current standard, the 2016 revision of this standard also underwent some changes that might be relevant to current users.

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 also were 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).