Atlas Shrugged: The Burden of Energy Performance
As an architect or engineer striving to increase building energy performance, do you often feel the weight of the world on your shoulders? The combined load of client expectations, the 2030 Commitment, energy models addressing multiple baselines, and LEED documentation, must all be optimized within budget constraints as you struggle toward the distant beacon of net zero energy.
Once the building is occupied and performance is tracked, you might feel more like Sisyphus than Atlas. Although you strained and sweated to push the energy performance rock to the top of the hill, your efforts can be easily undone by operating decisions and occupant behavior. And who gets blamed if performance is not as predicted? It’s been hard to find good research investigating the relative impact of design, operations, and tenant behavior on building performance, but a July 2011 New Buildings Institute White Paper goes a long way to help.
Sensitivity Analysis: Comparing the Impact of Design, Operation, and Tenant Behavior of Building Energy Performance, by Jonathan Heller and Morgan Heater of Ecotope and Mark Frankel of New Buildings Institute, compares the relative magnitude of modifications to design, operation and tenant behavior characteristics on the total building energy use of a mid-size office building. Twenty-eight distinct physical and operational building characteristics that affect total building energy use were identified for study purposes, each with a range of performance values representing poor, baseline and good practice with respect to building energy performance. To represent interactive effects (i.e. impacts from interactions between systems such as cooling and lighting), good and poor practice packages of measures were also analyzed. Weather data from 16 different cities represented the range of U.S. climate types.
The authors identify the general perception that “the responsibility for building energy performance is in the hands of architects and engineers and is relatively set once the building is constructed.” They explain why this research should serve an important function and overturn that assumption.
“This perception represents a significant barrier to broad societal goals to substantially improve building energy performance and reflects an extremely inaccurate perception of how buildings work. 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.”
The study deserves a broad, diverse set of readers. As the authors suggest, the implications of their work extend far beyond the interests of the design community:
“While the results of this study are informative to the design community in prioritizing energy strategies for buildings, they have even more significant implications on how buildings are operated and occupied and on how design teams should communicate information about building performance to building owners, operators and occupants. The results of this study can provide a broader perspective on how buildings use energy and on what aspects of building energy performance deserve more attention in design, operation and policy strategies.”
The white paper discusses some of the more significant implications related to energy modeling, energy codes, operation and occupancy assumptions and decision making, and climate responsive design strategies. Extremely useful graphics of the relative impacts will help spread these messages. Download the document here.