APPROVAL OF KUBO GROUP (KUBO)’S EXCEPTIONAL METHD FOR ANALYZING THE DESIGN OF A HEATED GREENHOUSE IN SANTA MARIA, CALIFORNIA

The California Energy Commission (CEC) adopts and regularly updates regulations for new construction, additions, and alterations to residential and nonresidential buildings, which are contained in California Code of Regulations, Parts 1 and 6 (the California Energy Code). These regulations go through an extensive public process and are adopted at a CEC business meeting before going into effect. Part 1 of the Energy Code includes administrative regulations for implementation. In certain circumstances, interested parties or the CEC may identify Exceptional Methods that meet the minimum requirements of the Energy Code, but that require additional regulatory action to ensure compliance and consistency with the Energy Code. In these situations, section 10-109(e) of the 2025 Energy Code states that, “The Commission may approve an exceptional method that analyzes a design, material, or device that cannot be adequately modeled using the public domain computer programs. Applications for approval of exceptional methods shall include all information needed to verify the method's accuracy.” On June 24, 2026, KUBO submitted an application for CEC approval of KUBO’s Exceptional Method for the specified project design that demonstrates compliance with mandatory requirements for nonopaque envelopes in conditioned greenhouses as provided by the 2025 Energy Code. The application included documentation that analyzed the performance of a conditioned greenhouse project in Santa Maria, demonstrating that the design meets or exceeds the equivalent requirements of Section 120.6(h). The application was available for public comment through July 24, 2026. No comments were received. CEC staff reviewed the application submitted on June 24, 2026, including supporting analysis, and all written comments submitted. CEC staff’s analysis confirmed that: 1. KUBO’s conditioned greenhouse design for the specified project in Santa Maria, CA cannot be adequately modeled by any of the public domain computer programs used to demonstrate compliance with the 2025 Energy Code, 2. The proposed Exceptional Method adequately models the performance of KUBO’s design for the specified conditioned greenhouse in Santa Maria, California,, and 3. The proposed Exceptional Method for analyzing KUBO’s design, as applied to the Santa Maria project described in the application, accurately demonstrates a modest reduction of the energy budget compared to the mandatory requirements for nonopaque envelopes in conditioned greenhouses in the 2025 Energy Code. CEC staff and the Executive Director recommended that the CEC approve KUBO’s proposed Exceptional Method that analyzes the design of a conditioned greenhouse project in Santa Maria, California, consistent with Section 10-109(e). KUBO’s Exceptional Method was approved at the CEC’s August 17, 2026 Business Meeting.