Energy efficiency in buildings has garnered significant attention in Saudi Arabia. This paper outlines the potential effects of higher residential efficiency on electricity load profiles in the Kingdom. It further presents the associated benefits that could have been realized by the local utilities in 2011. To perform the analysis, we designed an integrated methodology in which an engineering-based residential electricity demand model is used within an economic equilibrium framework. The modeling approach allows us to capture the physical interactions arising from higher efficiency and the structural changes that could occur in the economy beyond the end-consumers. Raising the average air-conditioner energy efficiency ratio (EER) to 11 British thermal unit (BTU)/(Wh) from its 2011 average would have saved 225,000 barrels/day of crude oil in electricity generation. Alternatively, increasing the share of insulated homes from 27 to 64 % would have allowed the power sector to lower its use of the fuel by 158,000 barrels/day. Combining both measures in a single simulation yields incremental yet not additive reductions. All alternative scenarios reduce costs to the utilities and improve the average thermal efficiency for the electricity generated. The studied efficiency options shift the load curve downward during the peak load segment when the least efficient turbines would be used. We additionally show how efficiency improvements in end-uses can affect the decisions of other sectors in the economy.