Table 1. Single-Family Models – Site Energy Comparison for All Models (kWh). This table summarizes annual site energy use (kWh) for the single-family prototype by climate zone (before PV) comparing: CBECC prescriptive baseline; CBECC–PH Design 1 and CBECC-PH Design 2 equivalent models; and PH Design 1 and PH Design 2 models. In this table, The CBECC-PH equivalent designs are the results of the PH certified designs modeled in CBECC. PH Design 1 and 2 are the results directly from each PH software.
The study also shows that PH construction cost premium estimates can be fairly modest, generally in the 0–5% range relative to code compliant baselines, in more mature PH markets. Limited familiarity and perceived high cost remain obstacles in California, with the largest drivers of cost premiums being high-performance windows, additional exterior insulation, and airtightness detailing. As market familiarity, supply chains, and workforce capacity improve within California, lower premiums can be realized.
Some opportunities for code and software improvement also come to light, such as targeted enhancements to CBECC and Title 24, including development of a formal modeling guide for PH-related projects, improving how airtightness and HRV/ERV systems are credited and others.
Finally, the study offers some policy and market recommendations. These include integrating PH-based or PH-aligned compliance options in future code cycles (e.g., 2031), expanding incentives, training, and pilot projects, developing a PH-capable workforce and creating clear crosswalks and documentation for PH elements in Title 24.
Q: Are there opportunities for local government in this area? Put another way, why should local government staff care about Passive House requirements?
A: Great question! As you know, last fall Governor Newsom signed AB368 into law. This legislation directs the California Energy Commission (CEC) to study the cost effectiveness of Passive House Standards to determine the feasibility of including Passive House standards in the statewide Building Energy Efficiency standards as an alternative compliance pathway. The CEC has until July 1, 2028 to complete its study.
At the local level, cities or counties can explore reach code measures that set higher performance requirements than the base Title 24 code, specifically referencing PH standards for airtightness, insulation, and ventilation. Of course, reach code development using PH standards would also require cost-effectiveness analysis.
The study explores some activity in other states (e.g., Massachusetts and New York) in this area, demonstrating the opportunity for incentivizing PH certification for certain building types, especially multifamily and affordable housing.
Launching local pilot projects or demonstration buildings that pursue PH certification can showcase feasibility, build local expertise, and provide real-world data on costs and performance. These projects can serve as case studies for broader adoption and help de-risk PH for local developers and builders.
Q: Finally, what are some practical next steps that local jurisdiction staff can take if they have an interest in exploring this further?
A: If a local jurisdiction is interested in learning about Passive House reach code opportunities, please reach out to the statewide Local Energy Codes team. Cities and counties can also undertake outreach activities focused on builders to educate them about the benefits of PH, offer resources and perhaps even incentivize PH projects.
This study is available free of charge here, including information about PH-related efforts in other jurisdictions. Other PH resources include Passive House California, PHN, and PHIUS.