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Residential Quality Insulation Installation (QII)

Measure Description

Under the 2013 and 2016 code, a compliance credit is awarded for installations that perform Quality Insulation Installation (QII). The Standard Design assumes that builders are not performing QII and wall insulation values are modeled at 70 percent of the R-value of the installed insulation, with attic defects assumed as well. If a builder performs QII, the actual insulation values (100 percent) are credited in the modeling. Fiberglass batt insulation is still the most commonly used wall insulation product used in California, while loose-fill fiberglass insulation is commonly used in attic insulation. The proposed 2019 effort will change QII from a compliance credit to a prescriptive requirement for all climate zones, except low-rise multifamily buildings in Climate Zone 7. Verification by a Home Energy Rating System (HERS) rater will be required to ensure proper insulation installation within the entire thermal envelope (including walls, roofs, and floors). QII will remain a compliance credit for multifamily buildings in Climate Zone 7. This prescriptive measure does not apply to alterations.

Making QII part of the prescriptive package will ensure that more insulation installations are properly implemented, increasing the effective U-factor of these envelope assemblies. This measure will modify existing code language but does not modify the scope of the standards. If QII becomes a prescriptive requirement, it will result in a modification of the prescriptive package, and be removed as a compliance credit in all applicable climate zones. The measure will also require an update to the Joint and Residential Appendices language, and compliance documents, as related to QII requirements. If added to the prescriptive package, QII will be part of the basis for the performance approach for building envelope measures.


The Statewide CASE Team 2019 Title 24, Part 6 Final CASE Report is available below. The Final CASE Report incorporates feedback received during utility-sponsored stakeholder meetings, Energy Commission Pre-Rulemaking workshops, and personal communication with stakeholders.

Presentations and Meetings

  1. Presentation from Stakeholder Meeting on September 14, 2016
  2. Notes from Stakeholder Meeting on September 14, 2016
  3. Presentation from Stakeholder Meeting on March 14, 2017
  4. Notes from Stakeholder Meeting on March 14, 2017

Code Language

  1. Draft Code Language – March 2017


  1. Impact of Insulation Installation Quality – Diana Fisler, Ph.D. & John B. Smith, P.E.


  1. CASE Results Report
  2. Final CASE Report
  3. Draft CASE Report

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.