More homes across the United States have air conditioning than ever before. The saturation of residential AC has risen dramatically over the last several years, from 56% in 1978 to over 75% in 2001.

In this report, we examine this trend and address a number of key questions: How is increasing AC saturation affecting typical residential load shapes and system load shapes? How do those altered load shapes in turn affect distribution facilities, load forecasting, and cost allocation and pricing? Finally, we look at ways that utilities are or could be dealing with the situation, including promoting demand response programs, technology changes, and efficiency standards.