NBI Study Shows Impact of Design Decisions and Operations and Tenant Behavior on Building Energy Use

With growing energy needs to run equipment and more complex HVAC and lighting systems in today's commercial buildings, architects and engineers can only go so far in delivering on energy efficiency. A new study by New Buildings Institute (NBI) summarizes the extent to which operations and occupant behavior impact a building's energy use compared to design characteristics.

The study, which was developed jointly with Ecotope in Seattle, Wash., also makes recommendations for design teams, owners and operators on what they can do to ensure the full potential for energy savings from efficiency measures is realized. NBI is a national, nonprofit organization working to improve the energy performance of commercial buildings. Ecotope provides research, design, and analysis for projects targeting deep energy efficiency outcomes.

The study, "Sensitivity Analysis: Comparing the Impact of Design, Operation, and Tenant Behavior on Building Energy Performance," provides a broad perspective on how buildings use energy and what aspects of building energy performance deserve more attention in design, operation and policy strategies. Most significantly, the study suggests that although the market generally assigns responsibility for building energy performance to the design team for aspects such as envelope, HVAC system and lighting system features, operational and tenant practices have a very significant impact on building energy use.

For example, decisions about the efficiency levels of the lighting and controls systems are fully under the purview of the designers, however the ultimate effectiveness of the lighting controls is more in the hands of building operators and occupants.

"The perception that energy performance is relatively set once the building is designed and constructed is not valid," explains NBI Technical Director Mark Frankel, an author of the report.

"In fact, a significant percentage of building energy use is driven directly by operational and occupant habits that are completely independent of building design, and in many cases these post-design characteristics can have a larger impact on total energy use than many common variations in the design of the building itself," Frankel said.