Big Efficiency Squeeze
Patterns of Code Compliance in California Buildings
California is gearing up to comply with the requirement that all new nonresidential buildings be zero net energy (ZNE) by 2030. A key strategy in reaching this goal is regularly adopting more stringent building codes and appliance standards, such that all new nonresidential buildings will be ZNE by 2030. This strategy gives Title 20 (the California Appliance Efficiency Regulations) and Title 24 (Part 6) (the California Building Energy Efficiency Standards) a proactive and key role in market transformation. Pacific Gas and Electric, Southern California Edison, Southern California Gas, and San Diego Gas and Electric, the state’s investor-owned utilities (IOUs), play a major role in advancing this market transformation through codes and standards development and enhancement efforts, education and training, and compliance improvement efforts. The IOUs recognize that the desired impacts of the codes are not achieved unless buildings comply with the code. To target their efforts most effectively, the IOUs wanted to develop a better understanding of the decision-making processes that affect Title 24 compliance. The IOUs specifically asked two questions:
- What are the building characteristics of compliant versus non-compliant buildings?
- What are the decision-making processes that lead some building project design teams to significantly exceed new code requirements while others are unable to comply or barely comply?
Cadmus reviewed building characteristics, ASHRAE Level II audit results, and Title 24 code compliance data that we collected for a sample of 91 new nonresidential buildings, permitted under Title 24 2008. Cadmus had previously used this data to evaluate the electric and gas savings associated with the IOUs’ 2010-2012 Codes and Standards Program. We used building energy simulations to calculate energy compliance margins for the building (as a whole) and its systems (e.g. HVAC, envelope, and lighting). We calculated the compliance margins by comparing the energy consumption of the as-built building and its systems to a minimally compliant baseline.
Cadmus used a variety of statistical techniques such as cluster analysis, data visualization, and regression analysis to identify trends in energy compliance margins based on building characteristics. To provide additional insight, we performed a literature review focused on the decision-making processes of compliant versus non-compliant buildings. We also interviewed 10 decision-makers involved in the design, construction, and code compliance modeling of a sample of the surveyed buildings.
We found that building type was the only significant building characteristic driving whole-building compliance with Title 24. Auto care/maintenance, gas stations, research/laboratories, and restaurants were under-compliant, or were not significantly associated with positive compliance margins. When looking at electric savings on average, the 91 sampled buildings tended to over-comply in HVAC and lighting efficiency while under-complying in envelope efficiency. Our interviews with decision-makers also pointed to gaps in the compliance modeling process, where envelope is the least scrutinized aspect of the building, while efficient lighting design is counted on to bring the modeled building into compliance. This presentation will review our interview results and findings of our sampled building data analysis.
Presented at the Behavior, Energy and Climate Change Conference in 2018 on Energy Efficiency as a Resource on October 16, 2017. Presentation by Sahar Abbaszadeh of Cadmus.