Annual energy consumption of a 1200 square foot residential home was modeled using four energy modeling programs: CBECC-Res, BEopt, EnergyPro, and REM/Rate. A baseline house was developed that met California Title 24 Standards, and both slab and crawlspace foundations were considered. The baseline house was additionally modified to have non-compliant (lower-efficiency) inputs, as well as advanced-efficiency inputs, for parameters including insulation, window properties, HVAC system efficiencies and air infiltration. For given set of inputs, the four models produced significant variations in calculated annual electricity and natural gas consumption with differences as high as +/- 50%.