British thermal unit BTU

SymbolBTU
SystemImperial & US Customary
QuantityEnergy
Value in SI≈ 1055.056 J (International Table)

About the British thermal unit

The British thermal unit is roughly the heat needed to raise one pound of water by one degree Fahrenheit, about 1055.06 joules in its International Table form. Air conditioners and furnaces in North America are rated in BTU per hour. Several slightly different definitions exist depending on the reference temperature.

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