As we all know, greener and cheaper energy is getting a lot of research and industrial focus these days. A little considered effect of this is the rebound effect, which states that people tend to use the money saved on energy for other energy consuming activities, which may offset the environmental benefits that could be gained. For example, the more cheaper fuel becomes, the more will people travel and consume more fuel. Similarly, the more cheaper home heating systems become, the more they will be used by those people who could not afford home heating so far. Estimates on the rebound effect vary, but can be as high as 30% of the savings.