ANSI/ASHRAE Standard 90.4-2022, Energy Standard for Data Centers - ASHRAE fact sheet
ASHRAE
A two-page ASHRAE Government Affairs fact sheet on Standard 90.4-2022: purpose, the MLC and ELC compliance metrics, scope thresholds, code adoption and changes since 2019.
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Overview
This two-page fact sheet introduces ANSI/ASHRAE 90.4-2022, the energy standard written specifically for data centres. The standard sets minimum energy efficiency requirements for them. Its scope threshold is a power density above 20 W/ft2 together with an IT load above 10 kW. The sheet is a summary aimed at policymakers, not the standard itself.
Compliance rests on two metrics. The mechanical load component (MLC) is the maximum ratio of all cooling, fan, pump and heat-rejection power to data centre power. The electrical loss component (ELC) is derived from the worst-case losses of each segment of the power chain. Cooling and electrical distribution are therefore limited separately.
On the regulatory side, the sheet notes that since 2019 Standard 90.1 has referenced 90.4 as an alternative compliance path for large computer rooms. The 2021 and 2024 IECC, in section C403.1.2, require compliance with Sections 6 and 8 of 90.4-2016 and 90.4-2022 respectively. This shows the standard being tied directly into model energy codes.
Compared with the 2019 edition, the 2022 edition lowers the MLC and ELC limits, adds a renewable-energy credit and a heat-reclaim credit, and removes the incoming service segment from the ELC. The limit of the document is that it contains no calculation method or limit tables, so the full text of the standard is needed for those. Copyright is held by ASHRAE; this page rests only on short paraphrased summaries.
Key points
- The standard applies to data centres with power density above 20 W/ft2 and IT load above 10 kW.
- MLC: maximum ratio of all cooling, fan, pump and heat-rejection power to data centre power.
- ELC: derived from the worst-case losses of each power-chain segment.
- Since 2019, Standard 90.1 references 90.4 as an alternative compliance path for large computer rooms.
- The 2021 and 2024 IECC (C403.1.2) require compliance with Sections 6 and 8 of 90.4-2016 and 90.4-2022 respectively.
- The 2022 edition lowers MLC and ELC, adds renewable-energy and heat-reclaim credits, and removes the incoming service segment from ELC.
Using it in design
- In the compliance calculator, compute annualised MLC and design ELC per segment (UPS, distribution, PDU) and compare them with climate-zone limits.
- Exclude the incoming service segment from the ELC calculation for the 2022 edition.
- Model renewable-energy and heat-reclaim credits as separate inputs.
- Automatically check the standard's scope thresholds (20 W/ft2 and 10 kW) at the start of a project.
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Who should read it
Data centre designers, consultants and policymakers verifying energy-code compliance.
Related standards
- ANSI/ASHRAE Standard 90.4-2022
- ANSI/ASHRAE/IES Standard 90.1
- IECC
Publication details
- Authors
- ASHRAE
- Publisher
- ASHRAE
- Year
- 2022
- Document number
- ANSI/ASHRAE 90.4-2022 (product 86237)
- Document language
- English
- Source type
- Standard
- Access
- Free to read
- Licence
- Copyright retained; citation only — the publisher’s terms apply to the original document
Original licence note
Free download from ASHRAE but (c) ASHRAE, all rights reserved; ASHRAE also prohibits entering its publication content into AI tools. Metadata/citation only; facts limited to short paraphrase.
Citation
ASHRAE (2022). ANSI/ASHRAE Standard 90.4-2022, Energy Standard for Data Centers - ASHRAE fact sheet. ASHRAE. ANSI/ASHRAE 90.4-2022 (product 86237). https://www.ashrae.org/file%20library/about/government%20affairs/advocacy%20toolkit/virtual%20packet/standard-90.4-2022-fact-sheet.pdf
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Related sources
All sources on this topicASHRAE 2023
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- The authors argue that standardised tools would encourage states to adopt 90.4.
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Energy and AI (World Energy Outlook Special Report)
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U.S. DOE FEMP / NREL 2024
Best Practices Guide for Energy-Efficient Data Center Design (Revised July 2024)
Weigh the supply air setpoint against server fan energy: raise it in small steps within the ASHRAE recommended range so the most demanding inlet nears 80 °F, only after air management is in place, and control to IT inlet temperature rather than return temperature.
- Compute racks reached 60 kW in 2013, and recent liquid-cooled racks exceed 125 kW.
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Consulting-Specifying Engineer 2019
ASHRAE's energy standard for data centers turns three
Implement the 90.4 MLC and ELC calculators with the correct test load points per UPS redundancy class (N/N+1 vs 2N).
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U.S. DOE Better Buildings / Lawrence Berkeley National Laboratory 2017
Data Center Metering and Resource Guide (February 2017)
At a stand-alone site, design meters that record energy (kWh) at the utility entrance and at the UPS output (or at panels serving only IT if there is no UPS); a UPS display that shows only power (kW) is not enough.
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