UC Davis

We compared the energy simulations of a Zero Energy Office Building (ZEB) at the design stage to its energy consumption during operation. The ZEB was located near San Francisco, California. This comparison was difficult because simulations used different categories than energy data collected through sub-metering. Overall, actual net energy was higher than simulation by 47%, while actual HVAC & lighting energy use were lower than simulation by 34% and 26% respectively. Actual plug energy use was more than 800% higher than simulations. Water heating energy disappeared as a separate end use because decentralized, plug-in units replaced a central unit.