While the times of sunrise and sunset change at roughly equal rates as the seasons change, proponents of Daylight Saving Time argue that most people prefer a greater increase in daylight hours after the typical "nine-to-five" workday. Supporters have also argued that DST decreases energy consumption by reducing the need for lighting and heating, but the actual effect on overall energy use is heavily disputed.

What two sources of energy use do DST proponents say are reduced by the time change?