Energy efficiency may refer to:
- Efficient energy use, sometimes simply called energy efficiency.
- Energy efficiency in transportation.
- Energy conversion efficiency, the ratio between the output and input of an energy conversion machine.
- Energy conservation, efforts made to reduce energy consumption.
Famous quotes containing the words energy and/or efficiency:
“The persons who constitute the natural aristocracy, are not found in the actual aristocracy, or, only on its edge; as the chemical energy of the spectrum is found to be greatest just outside of the spectrum.”
—Ralph Waldo Emerson (1803–1882)
“Nothing comes to pass in nature, which can be set down to a flaw therein; for nature is always the same and everywhere one and the same in her efficiency and power of action; that is, nature’s laws and ordinances whereby all things come to pass and change from one form to another, are everywhere and always; so that there should be one and the same method of understanding the nature of all things whatsoever, namely, through nature’s universal laws and rules.”
—Baruch (Benedict)