Green building codes have failed to conserve energy use in the nation’s most populated state, according to a new study published by the National Bureau of Economic Research.
California, currently home to 12 percent of the United States population, enacted energy building codes for the first time in 1978. The codes were projected to reduce residential energy use and its associated pollution by 80 percent. Instead, buildings constructed after the green energy codes took effect are not using less energy than homes built prior to the codes.
The supposedly-green codes added $8,000 to the construction cost of a new home. That’s essentially an $8,000 tax on new homes, with little public benefit.
The study was conducted by Arik Levinson, an economics professor at Georgetown University. Levinson’s results were published by the NBER Working Paper Series.
Levinson recognized that analyzing the effect of the green building codes was not as simple as comparing energy use between efficient and inefficient buildings. “People with larger energy needs may select energy-efficient homes,” he wrote. Pre-construction estimates of how much less energy a building will use because of the codes ignores the effect of cheaper energy on occupants’ overall consumption. Furthermore, California’s energy consumption cannot simply be compared to other states, because each state determines its own codes based on the energy use of its residents. These problems require more than a surface-level analysis to rectify.
Levinson did not only correct for issues that would bias results toward showing how ineffective green energy codes are. Recently built homes actually use more electricity than homes built prior to the 1978 building codes, but these homes are larger, built in warmer climates and have more residents than the pre-1978 homes, according to Levinson.
His research accounts for all of these effects through multiple approaches. For instance, Levinson measures the sensitivity of electricity use to temperature changes by analyzing zip code data on monthly utility bills and temperatures.
In the end, the evidence still shows that green building codes are ineffective. “There is no evidence that homes constructed since California instituted its building energy codes use less electricity today than homes built before the codes came into effect,” Levinson wrote.
Homes in California use less electricity than homes in other states, but this gap was unaffected by the implementation of building codes.
The codes may still make homes more energy efficient, but the lower cost of consumption increases energy use. Because of this, Levinson warned against using his research “as an indictment of building energy codes.”
California has the strictest energy building codes in the nation, according to the American Council for an Energy-Efficient Economy. It is the only state to receive a seven out of seven on the ACEEE’s building code ratings, calling it “one of the most aggressive and best enforced energy code in the United States.” Alaska receives the lowest score, at one out of seven.
