NEEA contracted Ecotope to quantify the energy use, energy savings, and incremental costs for residential codes in Washington. Ecotope compared the 2015 and 2012 residential energy code for single-family (including townhomes) and low-rise multifamily units; low-rise multifamily units are defined as 3-stories or less. The analysis estimated incremental energy savings and costs for the most recent round of the Washing State Energy Code (WSEC) change from 2012 to 2015. The study shows that single-family units in Washington have more incidence of gas heating compared to low-rise multifamily, where electric resistance heat is most common, which explains why, on a per dwelling basis, there is more electric savings for multifamily than single-family. Overall this represents 10.6% of the estimated energy use of the homes built to the 2012 WSEC.
