Persistence of Benefits from New Building Commissioning

Abstract

The commissioning process is gaining increasing recognition as a cost-effective strategy for reducing commercial building energy use. Although the success and costeffectiveness of commissioning activities depend on how well the benefits of commissioning persist over time, this aspect of commissioning is not well understood. The persistence of the benefits of commissioning new construction was recently studied as a part of the California Energy Commission Public Interest Energy Research program. Ten buildings that were commissioned as new buildings at least two years ago were evaluated. The commissioning reports, control algorithms, EMCS point measurements, and energy use data were examined to determine the persistence of selected items that were fixed during commissioning. Operator, owner, and commissioning provider interviews were conducted to help determine reasons for persistence and methods of improving persistence. The majority of the commissioning fixes that were studied persisted. The items that did not persist were typically changes in occupancy scheduling and cooling plant control strategies. The persistence of commissioning benefits was found to be highly dependent on the working environment for building engineers and maintenance staff. Through this investigation, we identified three main reasons that benefits of commissioning did not persist: limited operator support and high operator turnover rates, poor information transfer from the commissioning process, and a lack of systems put in place to help operators track performance. Four methods for improving persistence are proposed, focusing on operator training and system documentation.