An analysis of electrical billing data for single family customers of Austin Energy is performed with intent of identifying home electrical use impact of the energy codes adopted by the City of Austin. Information from multiple sources is combined to classify homes by house size, period of construction, energy efficiency program participation and owner or rental property. Electrical billing information from Austin Energy is used to analyze changes in energy use by the predetermined building characteristics for the time periods associated with building construction under adopted energy codes. Analysis of the data identifies that based on energy consumption in 2008, adoption of the 1986 Model Energy Code (MEC) reduced energy use for homes constructed between 1985 and 1995 by 9.1 GWh, a mean of 930 kWh per house or 7.3 percent of annual energy use. Homes built between 1996 and 2001, identified with the 1993 MEC, did not demonstrate a change in energy use when compared with homes built under the previous energy code. Adoption of the 2000 International Energy Conservation Code resulted in a total energy reduction of 3.5 GWh, a mean of 790 kWh per home or 5.8 percent of annual home energy use as compared to homes built under the 1993 MEC.Units: Dual