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Nonresidential Computer Room Efficiency

Measure Description

The computer room efficiency CASE Report will improve energy performance of computer room mechanical and electrical systems by including the following submeasures 

Uninterruptible Power Supply (UPS) Efficiency 

This submeasure proposes adding minimum UPS prescriptive efficiency requirements and testing requirements, based on ENERGY STAR, for AC-output UPS units used in computer rooms. The minimum average UPS efficiency considers UPS efficiency at 100%, 75%, 50%, and 25% load factors. 

Increased Temperature Threshold for Economizers 

This submeasure proposes simplifying the Title 24, Part 6, 140.9(a) prescriptive economizing requirements to a single outdoor air temperature condition for any economizer type, increasing the minimum outdoor temperatures for 100% economizing to 65°F dry-bulb or 50°F wet-bulb for any economizer type, and decreasing the computer room equipment load threshold for when air containment is required to 15 kW per room.  

 Computer Room Heat Recovery 

Computer rooms produce constant heat (24 hours per day, seven days per week). When a computer room is located in a facility that also has a heating load, recovered heat from the computer room can provide heating for the other facility heating loads while also reducing the cooling load on the computer room cooling system.  

This submeasure proposes adding prescriptive requirements for new computer rooms to include heat recovery if they fit into one of the following cases: 

  • Case 1 (computer room with nearby zones): Buildings with a total ITE1 design load exceeding 50 kW and with a design heating load greater than 200,000 Btu/hr where the heating zones are within 50 feet of the computer room. 
  • Case 2 (large computer room in building with large load): Buildings with a total ITE design load and a design heating load exceeding certain thresholds based on climate zone. 

Power Usage Effectiveness (PUE) Monitoring 

This submeasure proposes a mandatory requirement for computer rooms exceeding 2,000 kW ITE design load served by UPS to have metering installed to calculate Power Usage Effectiveness (PUE) and to provide this data to the building operator in an accessible manner.  

Mandatory Requirements 

This submeasure proposes the following 2019 Title 24, Part 6 prescriptive requirements become mandatory requirements:  

  • 140.9(a)2: Reheat 
  • 140.9(a)3: Humidification 
  • 140.9(a)5: Fan Control. 

Submeasures Moved to Future Code Cycles

The Statewide CASE Team is no longer pursuing the proposed changes listed below as it was determined that they did not meet the Energy Commission’s requirements for market readiness, technical feasibility, cost-effectiveness, or enforceability at the time they were considered.

Server Utilization Monitoring

Server utilization monitoring lets computer room operators know which servers are not being utilized and are therefore candidates for energy savings measures such as server virtualization or decommissioning. After initial research, including interviews with stakeholders, the Statewide CASE Team decided to stop pursuing server utilization monitoring for the 2022 code cycle for two reasons:

  1. Server utilization monitoring software and the servers on which it is installed are typically installed in the building after a certificate of occupancy permit is issued. This poses a significant regulatory hurdle for which the Statewide CASE Team does not have a viable solution at this time.
  2. Most server utilization monitoring software requires a monthly service subscription. Analysis is not currently showing this measure to be cost effective based on energy savings over the life of the measure.
Generator Crankcase Heating

Generator crankcases must be kept warm at all times, typically around 110°F, which is commonly done with a generator-mounted electric resistance heater. There are several options for reducing crankcase heater energy. After initial research the Statewide CASE Team decided to discontinue pursuit of this submeasure for the 2022 code cycle in an effort to focus on more cost effective measures.

Liquid Cooling Credit in Compliance Software

Using liquid cooling instead of air-cooled server cooling saves energy by eliminating mechanical supply fan energy and server fan energy. While this is a technology that is decades old, it is not common practice for most computer rooms.

The Statewide CASE Team investigated adding a compliance software credit for installing liquid cooling in computer rooms for the 2022 code cycle. Since this would not involve a code change requirement, the Statewide CASE Team decided to consider pursuing this submeasure outside of the CASE Report process.

Materials that the Statewide CASE Team developed when investigating this code change for the 2022 code cycle will be moved to the Future Code Cycles section of this website. Follow this link to find materials on computer room efficiency.

Relevant Documents

Measure proposals, supporting documents, and other outside references will be made public as they become available.

Round Two Utility-Sponsored Stakeholder Meeting Materials

Round One Utility-Sponsored Stakeholder Meeting Materials

Provide Feedback

This measure description will be updated as research is developed to support the 2022 code cycle. For questions or suggestions, email Include the measure name in the subject line.

Give Us Your Feedback

The Statewide CASE Team values input from all stakeholders engaged in the Title 24, Part 6 code change process. We encourage the open exchange of code change comments and concerns.

  • Use the form above to provide feedback on this measure.