High-Performance Walls: Insulation Solutions for California’s Energy Standards

Johns Manville Title 24 install

New energy efficiency regs through Title 24 require high-performance walls in homes.

By J. R. Babineau

In January 2017, the State of California implemented new energy efficiency regulations through Title 24. The update to the Residential Building Energy Efficiency Standards (Energy Standards) now requires new homes and updates to existing homes to be more energy efficient through LED lighting, reduced air leakage, tankless water heaters and increased R-value requirements for duct work in attics and walls.

Johns Manville insulation Title 24

Johns Manville insulation installer installs Johns Manville formaldehyde-free™ fiberglass batts or rolls over JM Corbond® spray-foam, combining the robust air-sealing benefits of foam with the cost-effective thermal and sound-control performance of fiberglass.

One significant change in the regulations will be to require high-performance walls in homes. These updates give California homeowners, builders and insulation contractors the opportunity to create a more energy efficient home, save money on energy bills and increase comfort, while positively impacting the environment. According to the California Energy Commission, the new mandates could cut regulated energy use in new homes by 28 percent and save consumers up to $31 per month on energy bills when compared to houses built in accordance to previous energy codes [Source: http://www.energy.ca.gov/releases/2015_releases/2015-06-10_building_standards_nr.ht].

Builders and insulation contractors can offer product solutions that meet these new codes within desired project budgets. With one of the broadest product offerings in the insulation industry, Johns Manville can help builders and insulation contractors find energy efficient solutions that meet the new Energy Standards.

Meeting Specific Requirements

Insulation requirements are measured in R-values and U-factors and can vary based on the project’s climate zone; climate zones are determined based on energy use, temperature, weather and a variety of other factors. R stands for resistance to heat flow and the higher the R-value, the greater the insulating power and heat flow resistance. U-factors are used to rate door or window units, as well as wall assemblies including insulation and framing. The lower the U-factor, the more energy efficient the system will be.

In climate zones 1-5 and 8-16, wall assemblies must not exceed a maximum U-factor of U-0.051, requiring R-19 cavity insulation plus R5 rigid insulation in 2×6 framing and R15 cavity insulation plus R8 rigid insulation in 2×4 framing. In climate zones 6 and 7 the maximum U-factor for wall assemblies is U-0.065. Determining which products will meet these new standards requires understanding of the framing type and spacing, the cladding, the current insulation type and how different products can work together.

Leveraging Product Combinations

One way to meet these updated requirements is to combine insulation products. These hybrid solutions can help balance code compliance with diverse project budgets and needs. By combining different types of products, builders and insulation contractors can leverage the code-compliant advantages of one product type against the economical or flexible benefits of another.

For example, JM Corbond® spray-foam can be combined with Johns Manville formaldehyde-free™ fiberglass batts or rolls or JM Spider® Plus blow-in insulation to bring together the robust air-sealing benefits of foam with the cost-effective thermal and sound-control performance of fiberglass. Another common combination is installing batts or rolls throughout the structure, and using spray foam for hard-to-reach or hard-to-manage places, such as rim joists. This approach can reduce overall air leakage, enhance the building envelope and extend the life of the HVAC system, all at a manageable cost.

High-Performance Wall Solutions

When meeting code requirements and maximizing energy efficiency, install quality and good design are pivotal in ensuring the building envelope is not only well insulated and sealed, but completely optimized.

Johns Manville spray foam title 24

Johns Manville insulation installer installs Johns Manville JM Spider Plus blow-in insulation with JM Corbond spray-foam.

Understanding how the different products in use can work together is important when delivering a high-performance wall system that meets the new Energy Standards. If unfamiliar with a particular product or how hybrid solutions work, take advantage of outside expertise through programs like JM TechConnect℠, for installation tips and troubleshooting.

Click here for more information on the Johns Manville insulation products that meet Title 24 requirements.


JR Babineau is a research manager and the principal building scientist for Johns Manville. For 20 years, he has been involved in research and development of building products, as well as providing education and consulting on building systems, with an emphasis on heat, air, moisture, noise, and energy efficiency.