Definition:British Thermal Unit

Definition

The British thermal unit is an imperial unit of heat energy.

It was originally defined as being:

the amount of heat required to raise the temperature of $1$ pound (avoirdupois) of water by $1$ degree Fahrenheit.

Conversion Factors

\(\ds \)

\(\)

\(\ds 1\)

British thermal unit

\(\ds \)

\(\approx\)

\(\ds 1055 \cdotp 06\)

joules

\(\ds \)

\(\approx\)

\(\ds 252\)

international calories

\(\ds \)

\(\approx\)

\(\ds 778 \cdotp 2\)

foot-pounds

Symbol

$\mathrm {Btu}$

The symbol for the British thermal unit is $\mathrm {Btu}$.

The $\LaTeX$ code for \(\mathrm {Btu}\) is \mathrm {Btu} .

Also known as

The British thermal unit is presented by some sources with all words capitalised:

British Thermal Unit

Sources

• 1969: J.C. Anderson, D.M. Hum, B.G. Neal and J.H. Whitelaw: Data and Formulae for Engineering Students (2nd ed.) ... (previous) ... (next): $1.$ Units and Abbreviations: $1.3$ British and other units
• 1998: David Nelson: The Penguin Dictionary of Mathematics (2nd ed.) ... (previous) ... (next): British thermal unit
• 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): British thermal unit