Electric heating

Electric heating uses relatively inexpensive tools to directly convert electrical energy into heat energy with a conversion efficiency of roughly 100%. Applications that are frequently used include industrial processes, cooking, water heating, and space heating. An electrical appliance that transforms an electric current into heat is called an electric heater. Every electric heater contains a heating element that is an electrical resistor and operates on the principle of Joule heating. When an electric current flows through a resistor, the electrical energy is transformed into heat energy. The active element in most contemporary electric heaters is nichrome wire; the heating element shown on the right is nichrome wire supported by ceramic insulators.

As an alternative, a heat pump, which uses electricity exclusively to transfer the thermal energy from the environment, primarily air, can achieve a heating efficiency of about 300%, or 3.0 Coefficient of Performance. The refrigeration cycle of the heat pump is powered by an electric motor, which pulls heat energy from the earth, outside air, or even the inside of a refrigerator, and transfers it to the area that needs to be warmed (in case of a fridge, the kitchen). This uses electricity considerably more efficiently than direct electric heating, but it also necessitates pipes and much more expensive equipment. For air conditioning, certain heating systems can be turned backwards, cooling the interior while venting much hotter air or water outside or into the earth.