This paper analyzes the 1992 and 2003 US Commercial Buildings Energy Consumption Survey microdata files to show the extent to which certain heating, cooling, lighting, and window technologies are entering use, and the resulting impacts on the intensity of energy use. Excepting the case of fluorescent lights, no technology dominates the entire market but instead each conquers a specific niche. Most of the buildings in which these technologies are installed do not have lower-than-average energy intensity, measured as annual energy use per square meter of floor space. The exceptional technology that does measurably correlate with reduced energy intensity is daylighting. These results suggest that technologies are adopted to serve comfort or quality objectives rather than to save energy, or that buildings’ users confound the designers’ intentions. Decision makers thus should improve operating and maintenance practices, invest in building commissioning, and rely more heavily on passive design features to save energy.