Three identically oriented homes were used for the study. Two of the homes were identically constructed using wood frame/stucco construction while the third used a wall of sandwiched Styrofoam in between concrete layers. It was found that the concrete house on the average consumed about 15% less energy for HVAC operation than the wood frame houses. Also the photovoltaic array placed on the roofs of two of the houses indicated a reduction in electrical energy consumption from the grid of about 20% of the HVAC electrical energy consumed. TRACE-700 simulation runs were made on both types of houses to determine the design cooling load for each of the houses and the total consumed electrical energy for each house over the whole year on a monthly basis. It was found that in the summer a 20% reduction of electrical energy for HVAC is predicted due to the use of the concrete house as compared to the wood frame homes. In addition a linear correlation was found to represent reasonably well the variation of the daily kilowatt hour versus the daily degree day value for a typical summer month in the Las Vegas, Nev. valley for all three houses. The slope of that line for the concrete home was about 24% less steep than the line for the wood frame construction confirmation in part theoretical calculations that this wall construction is more energy conserving than the base case.