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Nonresidential Opaque Envelope (based on ASHRAE 90.1)

2016 Title 24 CASE Topics

Measure Overview

The proposed measure would apply to all newly-constructed nonresidential and high-rise residential buildings in California. The updates to the prescriptive requirements are tailored for each climate zone, and will also serve as the basis for the standard design in the performance method.

The proposed change would modify prescriptive requirements and the standard design (reference for comparison) for the performance approach of the Standards. In addition, the proposed requirement would require minor updates to Reference Appendix JA4 to accommodate any new construction assemblies that are the basis of the prescriptive requirements.

This proposed measure does not provide requirements for new systems or equipment, does not modify modeling algorithms, and does not change or expand the scope of the Standards.

The proposed code change would provide updates to Tables 140.3-B, 140.3-C and 140.3-D in the Standards, and minor updates to Reference Appendix JA4, for the metal building roof assembly.

The list below provides a summary of how each Title 24 documents will be modified by the proposed change (underline indicates new language being added, strikethrough indicates existing language being deleted):

  • Standards: The proposed code change will modify Section 140.3 of the Standards. The proposed language will modify Tables 140.3-B and 140.3-C.
  • Appendices: The proposed code change may include modification to Reference Appendix JA4 to the Standards.
  • Nonresidential Alternative Calculation Method (ACM) Reference Manual: The proposed code change will modify section 5.5 /Nonresidential ACM Reference Manual. The only change will be to modify the standard design construction assemblies and associated U-factors for roofs, walls and floors to be consistent with the new proposed prescriptive requirements.
  • Compliance Forms: There are no significant changes to the applicable compliance forms as a result of this measure.

Stakeholder Meeting

Several stakeholder meetings and CEC staff workshops were held regarding the Nonresidential HVAC Economizer Modifications building energy efficiency topic. The list of past meetings and hearings can be found here. If you would like to receive email updates on this CASE topic, click the link below.


  1. Final CASE Report