This seminar will provide details about a recent project to examine a large-scale appliance replacement program in Mexico that since 2009 has helped 1.5 million households replace their old refrigerators and air-conditioners with energy-efficient models. Using household-level electric billing records from the population of Mexican residential customers we find that refrigerator replacement reduces electricity consumption by an average of 11 kilowatt hours per month, about a 7% decrease. We find that air conditioning replacement, in contrast, increases electricity consumption by an average of 6 kilowatt hours per month, with larger increases during the summer. To put these results in context we present a simple conceptual framework in which energy-efficient durable goods cost less to operate, so households use them more. This behavioral response, sometimes called the “rebound” effect, is important for air-conditioners, but not important for refrigerators.