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Quality Insulation Installation (QII)

Residential Envelope

Codes and Standards Enhancement (CASE) Report

The Statewide CASE Team is requesting feedback on the 2019 Title 24, Part 6 Draft CASE Reports. The CASE Report presents pertinent information that supports the code change proposal. Please email feedback to You may also submit written comments to the Energy Commission. See the agenda for Energy Commission pre-rulemaking workshop (available here) for instructions on how to submit comments to the Energy Commission’s docket.

Draft CASE Report: Residential Quality Insulation Installation (QII)

Measure Description

Under the 2013 and 2016 Title 24, Part 6 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 insulation and draft stopping defects between the attic and the conditioned zone 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 credit to a prescriptive performance requirement for all climate zones, except low-rise multifamily buildings in Climate Zone 7, and require verification by a HERS Rater to ensure proper insulation installation within the entire thermal envelope (including walls, roofs, and floors).

This prescriptive measure will apply to single family and low-rise multifamily buildings, and both new construction and additions. Including QII as part of the prescriptive package will ensure that the majority of insulation installations are properly implemented, increasing the effective U-factor of these envelope assemblies. This measure will modify existing code language, but will not modify the scope of the standards. If QII is added to the prescriptive package, it will be part of the basis for the performance approach for building envelope measures and will result in a modification of the prescriptive package as well as be removed as a compliance credit. The measure will also require an update to the Joint and Residential Appendices language and compliance documents, as related to QII requirements. QII procedures will also be expanded to address insulation methods, materials, and techniques not adequately covered under the current QII inspection procedures.

Request for Feedback

The Statewide Utility Team encourages participation in the CASE Report development process through the submission of data—both primary sources and references to existing data. We are requesting data on areas such as energy savings, costs, market impacts, industry practices, barriers to code compliance, etc. from stakeholders. The data will inform the energy savings estimates, cost-effectiveness analysis, compliance and enforcement, and market impacts that will be presented in CASE Reports.

Do you have feedback or data to share? Send us an email at

California Statewide Utility Codes and Standards Program

This program is funded by California utility customers and administered by Pacific Gas and Electric Company, Southern California Edison, San Diego Gas and Electric Company, Southern California Gas Company, Sacramento Municipal District, and Los Angeles Department of Water and Power in preparation for the California Energy Commission’s Codes and Standards Buildings Advocacy.