August 30, 2006—A recently released study of low-energy, high-performance commercial buildings in the US reveals that while the buildings do save energy as designed—25 to 70 percent lower energy consumption than allowed by code—more can be done to achieve the Department of Energy’s goal to achieve marketable zero-energy buildings by 2025. Zero energy buildings are designed, constructed, and operated to generate the same amount of energy they use each year.
The study, commissioned by DOE’s Building Technologies Program and conducted by the National Renewable Energy Laboratory (NREL), analyzed six buildings that represent the current generation of low-energy commercial structures.
These buildings were designed to meet low-energy and sustainability goals by using innovative combinations of energy technologies such as daylighting, radiant heating, natural ventilation, photovoltaic systems, evaporative cooling, and passive solar strategies.
Key lessons outlined in the report include:
- Owners provide the main motivation for designing and constructing low-energy buildings;
- Setting measurable energy saving goals at the outset of the project is crucial to realizing low-energy buildings;
- Many decisions about including or not including building features are not motivated by cost;
- Today’s energy-saving technologies can substantially change how buildings perform when they are applied together and properly integrated in the design, installation, and operation of the building;
- An integrated whole-building systems design approach is needed to achieve energy goals;
- Buildings do not always operate as they were designed (e.g., plug loads are often higher than planned, daylighting energy savings might be lower, occupants do not follow energy savings strategies as instructed); and
- Energy performance must be tracked and verified following completion of construction.
Commercial buildings currently account for 18 percent of total energy consumption in the US , with lighting and heating as primary energy-consuming activities, according to DOE. DOE also reports that in the US , new commercial buildings are added to the building stock faster than old buildings are retired, so this research will help DOE prepare the next generation of low-energy commercial buildings.
The full report on Lessons Learned from Case Studies of Six High-Performance Buildings (.pdf file), including case studies for each building, detailed lessons learned, and additional information on zero-energy buildings and daylighting technology, is available from NREL.
