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energy · US / Europe · Modern

therm

variant
Record
M327
Definition quality
Variant-dependent
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Definition

US therm = 1.054804×10⁸ J; EC therm = 1.05506×10⁸ J

Reference value by variant

therm covers several documented traditions, each with its own value. Choose a variant below to see a figure.

History & use

NIST notes that the U.S. therm is legally defined for the U.S. natural-gas industry, while the EC therm is based on the International Table Btu and has a slightly different value.

Modern use

Modern use is context-dependent and varies by region or measurement system.

Sources & evidence

Source tier — · confidence high

Related measurements

joule

J

energy · International · Modern

SI derived unit of energy and work; 1 J = 1 N·m = 1 kg·m²·s⁻².

calorie

cal

energy · International · Modern / historical

The generic calorie is variant-dependent; NIST lists thermochemical, International Table, mean, 15 °C, and 20 °C calories.

variant

kilocalorie

kcal

energy · International · Modern / historical

A kilocalorie is 1000 calories, so its joule value depends on the calorie convention.

variant

British thermal unit

Btu

energy · International · Modern / historical

British thermal unit is variant-dependent; NIST lists IT, thermochemical, mean, and temperature-specific forms.

variant

electronvolt

eV

energy · International · Modern / historical

Non-SI unit accepted for use with the SI; 1 eV = exactly 1.602176634×10⁻¹⁹ J.

kilowatt-hour

kW·h

energy · International · Modern

1 kWh = exactly 3.6×10^6 J.