States that have not adopted the latest energy-efficiency standard for commercial buildings are foregoing an average reduction of almost 10 percent in energy consumed by new structures over 10 years, which would trim their energy costs and carbon emissions by over 12 percent, according to a study* by an economist at the National Institute of Standards and Technology (NIST).
As important, the sizeable reductions in energy use and carbon emissions are cost-effective, says NIST's Joshua Kneifel, who analyzed energy usage and other variables for more than 12,500 buildings across 228 U.S. cities. Overall, more stringent efficiency requirements do not increase total construction and future operation costs for new commercial buildings. In fact, the average life-cycle cost over 10 years decreases by an average of nearly 1 percent, Kneifel found.
The analysis reveals that there are energy-efficiency gains to be had nationwide. Even in the 31 states that have adopted the more recent update of the energy standard for commercial buildings,** only slightly more rigorous requirements—such as increasing the thermal efficiency of insulation and reducing lighting densities—can deliver substantial benefits.
Kneifel estimates that if all 50 states adopted a "low energy case" building design, newly constructed buildings would consume about 18 percent less energy in the average state. Over the 10-year study period, this average would translate into energy cost savings of more than 22 percent and a 20 percent reduction in energy-related carbon emissions. Building life-cycle costs over those 10 years would dip by about 1 percent.
The largest energy, cost and environmental benefits, of course, would go to the 11 states that today have no commercial building energy code and the three using the oldest version of the efficiency standard, which is updated about every three years by ASHRAE, a building technology standards organization. If these states adopted the study's low energy design, all 14 would realize at least a 25 percent decrease in their total energy use and reductions of about 30 percent in energy costs and carbon emissions.
Kneifel's analysis is based on computer simulations of how 11 different types of buildings—from high schools, restaurants and retail stores to office buildings, hotels and apartments—use energy. These building types represent 46 percent of the nation's commercial building stock floor space. The 228 cities included in the study were distributed across the nation and are representative of all climates across the country. The study also considered variation in energy sources and fuel mixes for electric power—for example, the percentages of power generated by coal or natural gas.
The NIST economist also conducted detailed analyses of seven states that represent the full range of state energy-efficiency codes, climate types, and new commercial building floor space added between 2003 and 2007. In addition to providing a wealth of comparative information on energy use and efficiency for the seven states, the analyses demonstrate the usefulness of a new NIST database and software tools that will debut in late 2013. Called BIRDS (for Building Industry Reporting and Design for Sustainability), the free, Web-based tool kit will further research, design, and planning efforts focused on building energy use and technologies to improve energy efficiency.
BIRDS complements NIST's Building for Environmental and Economic Sustainability tool (commonly known as BEES). Widely used in industry and government, BEES includes actual environmental and economic performance data for 230 building products and science-based techniques for selecting cost-effective, environmentally preferable building products.