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 more than 12 percent, according to a recent study by Joshua Kneifel, an economist at the National Institute of Standards and Technology (NIST).


It is just as important, Kneifel said, that the sizeable reductions in energy use and carbon emissions are cost-effective. Kneifel 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, Kneifel found that the average life-cycle cost over 10 years decreases by an average of nearly 1 percent.


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 on average. Over the 10-year study period, this average would translate into energy cost savings of more than 22 percent. 


The largest energy, cost and environmental benefits 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 ASHRAE updates about every three years. If these states adopted the study’s low-energy design, all 14 would notice 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 11 different types of buildings, which 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. The study also considered variation in energy sources and fuel mixes for electric power and the percentages of power generated by coal or natural gas.