'''Energy efficiency''' may refer to:
* Energy efficiency (physics), the ratio between the useful output and input of an energy conversion process ** Electrical efficiency, useful power output per electrical power consumed ** Mechanical efficiency, a ratio of the measured performance to the performance of an ideal machine ** Thermal efficiency, the extent to which the energy added by heat is converted to net work output or vice versa ** Luminous efficiency, a measure of how well a light source produces visible light ** Fuel efficiency, the efficiency of converting potential energy in a fuel into kinetic energy ** Energy efficiency in transportation, the fuel economy of various modes of transportation ** Energy-efficient landscaping, a type of landscaping designed for the purpose of conserving energy * Efficient energy use, minimizing the amount of energy used for a given, constant energy service * Energy conservation, reducing energy consumption by using less of an energy service
==See also== * Energy (disambiguation) * Efficiency (disambiguation) * Energy rating (disambiguation) * {{intitle}} * {{intitle|Energy efficient}}
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Energy efficiency