Energy and environment: Influence of energy saving technologies

Saving energy is a ubiquitous motto. Reducing energy use at any cost may backfire on the environment. Therefore it is necessary to investigate an energy saving measure with all its connections. E.g. a solar heating system reduces the heating costs, but needs additional electrical energy, transfers more heat to the environment, and uses up additional resources. Below the line it may not save as much energy, as promised by the salesperson. Case studies and life cycle analyses can help to clarify this question.