For energy efficiency in relation to economics, see energy conservation

In physics and engineering, including mechanical and electrical engineering, energy efficiency is a dimensionless number, with a value between 0 and 1 or, when multiplied by 100, is given as a percentage. The energy efficiency of a process is defined as:

$\backslash mathrm\{efficiency\}\; \backslash \; \backslash eta\; =\; \backslash mathrm\; =\; W\; /\; energy$

where W is the amount of useful work done by the process (in joules), and "energy" is the quantity of energy (again, in joules) used to run the process.

Energy efficiency within Newtonian physics systems cannot exceed 100%. For practical purposes, the only energy conversion that is 100% efficient is the conversion of electrical energy to heat.

Loudspeakers have a very low efficiency under 2 percent.

See also

External links

• Conversion of sensitivity in dB per Watt and meter to energy efficiency in percent for passive loudspeakers

Introductory physics

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