In 2009 the Washington State Legislature updated the legislation authorizing the Washington State Energy Code (WSEC). In the process, the legislature also set a goal that the total energy of new buildings would be reduced 70% over the performance of buildings built to the 2006 WSEC by the 2031 code cycle. To meet this ambitious goal the Washington State Building Code Council (SBCC) was authorized to develop incremental steps that would achieve this goal over the eight code cycles anticipated by 2031. The first step on that path was developed for the 2009 WSEC.

For the residential energy code an option table was devised that would allow builders to trade off various measures from a diverse menu of options. The SBCC was then sued under the theory that the federal preemption would prevent measures that exceed the equipment standards. The 9th Circuit Court upheld the option table in 2011. The option table was implemented. The 16 options were organized into 6 categories: envelope, ventilation, HVAC equipment, ducts, domestic hot water, and renewable credits (mostly solar PVs). Points were assigned to each option, roughly proportional to the savings anticipated from each option. Points varied from half a point to 2 points depending on the measure. In the 2009 code only one option point was required for single family homes. Subsequent code cycle added points to the requirements of the code mandating an increasing number of points for compliance. In addition the scope was later expanded to include low rise multi-family buildings. In the most current cycle (2015) 3.5 points was adopted for single family residences. The paper discusses the option table as a path to improve both the flexibility and efficiency of the energy code.