Energy harvesting (in German: energy harvest) refers to the gaining of energy from the environment. Existing energy is collected and used for other purposes.

A concrete example from the smart home area: Das essentials radiator thermostat energy self-sufficient BT is not powered by batteries, but draws the energy required for its function from the available heating heat via an integrated thermoelectric nanogenerator. The radiator thermostat is therefore not dependent on any other energy sources. This principle of energy self-sufficiency is called energy self-sufficiency.