The standard is evolving. The 2022 version introduced stricter ELC limits for transformers (moving towards NEMA TP-1 efficiency). The next revision (expected 2025) may include:
If you are designing a data center for a 10-year lifespan, you should download the current ASHRAE 90.4 PDF but also monitor the standing standard project committee (SSPC 90.4) for public review drafts.
If you have an old 2016 PDF, throw it away. The 2022 update changed the game:
Absolutely. For any professional involved in data center design, operation, or certification (LEED, ENERGY STAR, etc.), the cost of the official PDF pays for itself in avoided redesigns and code violations.
Recap of actions:
By mastering ASHRAE 90.4, you don't just save energy—you ensure uptime. Efficient data centers run cooler, suffer less maintenance, and reduce the risk of thermal runaway. Get the standard, learn the math, and build the future responsibly.
Disclaimer: This article is for informational purposes only. Standards are updated regularly. Always refer to the latest official ASHRAE 90.4 document for enforceable code requirements.
ASHRAE Standard 90.4, titled the Energy Standard for Data Centers, is a performance-based framework designed to establish minimum energy efficiency requirements for the design, construction, and operation of data centers.
While traditional buildings follow ASHRAE 90.1, 90.4 serves as its "sister standard," specifically tailored for the unique, mission-critical load requirements of high-density computing environments. Scope and Applicability ASHRAE 90.4 applies specifically to facilities where: Power Density is greater than 20 W/ft². IT Equipment (ITE) Load exceeds 10 kW.
It covers new data centers, additions to existing facilities, and major alterations that require new mechanical or electrical systems. Key Metrics: MLC and ELC
Unlike the common Power Usage Effectiveness (PUE) metric used for operational monitoring, 90.4 is a design standard that uses two primary components for compliance: ASHRAE 90.4 Standard For Data Center Cooling - AKCP ashrae 90.4 pdf
What is ASHRAE 90.4?
ASHRAE 90.4 is a standard published by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) that provides guidelines for the energy-efficient design of data centers. The standard focuses on minimizing energy consumption while maintaining the required level of reliability and performance.
ASHRAE 90.4 PDF: Key Points
Here are some key points to consider:
Helpful Blog Post Recommendations
While I couldn't find a specific blog post that directly provides an ASHRAE 90.4 PDF, here are a few helpful resources that discuss the standard:
Free Resources
You can obtain a free copy of the ASHRAE 90.4 standard from the ASHRAE website:
Purchase ASHRAE 90.4 PDF
If you want to purchase a PDF copy of the standard, you can do so from the ASHRAE website or other online marketplaces: The standard is evolving
ASHRAE Standard 90.4-2022 serves as the energy standard for data centers, focusing on specialized metrics like Mechanical Load Component (MLC) and Electrical Loss Component (ELC) rather than traditional PUE. It is frequently updated through a continuous maintenance cycle, with read-only versions and official PDFs available directly through ASHRAE. For more details, visit ASHRAE. Standards and Guidelines - ASHRAE
ASHRAE Standard 90.4-2019 provides a specialized energy-efficiency framework for data centers, focusing on the mechanical load component (MLC) for cooling and the electrical loss component (ELC) for power systems to meet specific PUE targets. The standard emphasizes a performance-based approach to design, aligning with thermal guidelines to ensure efficiency while maintaining equipment reliability. The official, copyrighted document for the standard can be acquired directly through the ASHRAE Bookstore.
I can’t provide or convert copyrighted standard PDFs like ASHRAE 90.4 into full text. I can, however, help in these ways — tell me which you want:
Which option would you like?
Understanding ASHRAE 90.4: The Data Center Energy Standard ASHRAE Standard 90.4 establishes the minimum energy efficiency requirements for the design, construction, and operation of data centers. Unlike broad building standards, 90.4 is specifically tailored to the unique, mission-critical load requirements of high-density computing environments.
The latest version is Standard 90.4-2025, which expands the scope of previous editions (2016, 2019, 2022) to include broader sustainability metrics like greenhouse gas emissions and water usage. Where to Find the ASHRAE 90.4 PDF
Official copies of the standard are not available for free as public downloads. To obtain the full, authorized version of Standard 90.4, you should visit official industry repositories:
ASHRAE Bookstore: The primary source for purchasing the ANSI/ASHRAE Standard 90.4-2022 or the latest 2025 edition in digital PDF or print.
ASHRAE Read-Only Versions: ASHRAE provides a Read-Only Version for public viewing of older editions (such as 90.4-2016 and 90.4-2019) to assist with code compliance.
Standard Fact Sheets: For a high-level summary without purchasing the full document, you can access the 90.4-2022 Fact Sheet directly from the ASHRAE website. Key Compliance Metrics: MLC and ELC If you are designing a data center for
ASHRAE 90.4 uses a performance-based approach, focusing on two primary components rather than just the traditional Power Usage Effectiveness (PUE) metric:
Mechanical Load Component (MLC): This calculates the sum of all power required for cooling, fans, pumps, and heat rejection equipment, divided by the total IT equipment power. Compliance factors vary by ASHRAE Climate Zone.
Electrical Loss Component (ELC): This measures the worst-case losses across the power chain, including the UPS segment and ITE distribution segment, to ensure a minimum level of electrical efficiency. ASHRAE 90.4 vs. ASHRAE 90.1
While ASHRAE 90.1 is the general energy standard for buildings, 90.4 acts as a specialized companion for data centers. What ASHRAE 90.4 does for data center energy efficiency
ASHRAE Standard 90.4, titled "Energy Standard for Data Centers,"
is a performance-based design standard established to create minimum energy efficiency requirements for data centers. Unlike the prescriptive Standard 90.1, Standard 90.4 is tailored to the unique, mission-critical load requirements of data center environments. Purpose and Scope Establish Efficiency
: Defines the minimum energy efficiency for the design, construction, and operation of new data centers or major modifications to existing facilities. Renewable Energy
: Provides a framework for using on-site or off-site renewable energy resources.
: Applies to new data centers and their systems, additions, and significant modifications. It generally excludes telephone exchanges and essential facilities. Key Metrics for Compliance
Standard 90.4 moves away from Power Usage Effectiveness (PUE) as a design metric, instead utilizing two primary components to determine compliance: Impact of ASHRAE guidelines for Data Centers? - AKCP
ASHRAE 90.4 is mainly used as a design standard applied when submitting approval plans before constructing a data center facility. ASHRAE 90.4 Energy Standard for Data Centers