How is Energy Measured?

Published Oct 22, 2013

Understanding BTUs, therms, quads, and more.

A British Thermal Unit (Btu) is a measure of energy content, usually used to describe the energy content of fuels. Because a Btu is so small, energy is usually measured in millions of Btus.

  • 1 Btu = the amount of energy required to increase the temperature of one pound of water (which is equivalent to one pint) by one degree Fahrenheit.  This is roughly the heat produced from burning one match. 
  • 1,000 Btu = four-fifths of the energy contained in a peanut butter and jelly sandwich. 
  • 100,000 Btu = one therm, such as what you would find on your gas bill.  One therm is roughly equal to the energy contained in 80 peanut butter and jelly sandwiches.  The average U.S. household used about 420 therms, or 42 million Btu, of natural gas in 2011 [1].
  • 312 million Btu = U.S. per capita energy consumption in 2011 [2].
  • 1 quadrillion Btu = one quad. The U.S. consumes more than 97 quads annually [3]. 


[1] EIA. Natural Gas Consumption Estimates, 2011.

[2] EIA. How much energy does a person use in a year?

[3] EIA. How much of the world’s energy does the United States use?

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