Natural experiments in Indiana showed that energy consumption increased when some counties made the transition to DST. The Department of Energy reported that as a nation we used less than 0.5% less energy in 2007 compared to 2006. However, the Indiana study explains that the only effective energy savings occurs in the early spring which is most of the difference between the DST periods of the two years compared in the DoE report. It is important to note that the Indiana study points out that this energy savings experienced in the early spring is offset by an increase in usage throughout the remainder of the DST period, most likely due to an increased use of air conditioning and heating. http://climateprogress.org/2010/03/13/daylight-saving-time-energy-dst/
The link to this study can be accessed below. http://www2.bren.ucsb.edu/~kotchen/links/DSTpaper.pdf
