Early Energy Use in New Commercial Buildings

Many utilities base the success of energy-efficiency programs for new buildings upon the energy used in the buildings' first or second year of operation. Recent research from Bonneville Power Administration's Energy Edge Project shows that the early years of operation for new commercial buildings are not representative of long-term performance.

Energy Edge assessed the potential for electricity conservation in new commercial buildings. From 1986 to 1993, the project evaluated the performance of 28 buildings designed to be 30% more efficient than required by the regional energy code. Monthly utility bills were compiled to track energy use trends over a longer period of time than the expensive end-use metering covered. On average, energy use increased during the first four years of operation with the rate of growth slowing each year. The figure shows 12-month rolling averages of annual energy use (sum of the previous 12 months) for the 14 office buildings. Up to six years of data are shown. Energy savings for individual energy-efficiency measures were estimated using building simulation models calibrated by these data.

Buildings with the steepest growth in energy use during early years of operation are large office buildings, which can take several years to be fully occupied. One twenty-story office building required additional cooling after a large computer software company moved in during the building's third year of operation, increasing energy use by 20%.