British thermal unit

noun

: the quantity of heat required to raise the temperature of one pound of water one degree Fahrenheit at a specified temperature (such as 39°F)

Did you know?

Despite its name, the British thermal unit, or BTU, may be more widely used in North America than in Britain. Air conditioners, furnaces, and stoves are generally rated by BTUs. (Though "BTUs" is often short for "BTUs per hour;" in air-conditioner ratings, for instance, "BTUs" really means "BTUs of cooling capacity per hour".) Fuels such as natural gas and propane are also compared using BTUs. The BTU first appeared in 1865 and isn't part of the metric system—the metric unit of energy is the much smaller joule—so it isn't much used by scientists, but its practicality keeps it popular for consumer goods and fuels. A better-known heat unit is the calorie; a BTU is equal to about 252 calories. (Since the familiar food calorie is actually a kilocalorie, a BTU equals only about a quarter of a food calorie.)

Examples of British thermal unit in a Sentence

Recent Examples on the Web

While tariffs could slightly increase U.S. natural gas prices, Goldman Sachs estimates the rise would be only a few cents per million British thermal units (MMBtu) above the current $4 level. —Dan Eberhart, Forbes, 19 Mar. 2025

Energy Transfer's Oasis Pipeline LP will provide as much as 450 billion British thermal units per day of natural gas to supply CloudBurst's data center campus outside of San Marcos, Texas, Energy Transfer said Monday in a statement. —arkansasonline.com, 11 Feb. 2025

Benchmark Henry Hub natural gas reached $3.66 per million British thermal units on Thursday, peaking at $4.20 earlier in the week. —Amanda Castro, Newsweek, 3 Jan. 2025

One British thermal unit is equivalent to 1,055 joules and will raise the temperature of one pound of water one degree Fahrenheit. —Matthew J. C. Clark, Harper's Magazine, 2 Aug. 2024

The price of natural gas surged more than 15% early Monday, nearing $4 per million British thermal units. —Jeff Marks, CNBC, 30 Dec. 2024

The Henry Hub natural gas spot price averaged $2.15 per million British thermal units (MMBtu) through December 16, falling short of 2023's $2.53/MMBtu average. —Robert Rapier, Forbes, 27 Dec. 2024

Analysts now predict that LNG prices in Asia could soar to over $20 per million British thermal units (mmBtu) if global supply tightens. —Dan Eberhart, Forbes, 12 Dec. 2024

The summer and fall have also been volatile — but in the past month, natural gas is up a little over 12% and traded just over $3 per million British thermal units on Friday. —Kevin Stankiewicz, CNBC, 6 Dec. 2024

Word History

First Known Use

1865, in the meaning defined above

Rhymes for British thermal unit

• lunate
• multiunit
• subunit

Kids Definition

British thermal unit

noun

: the quantity of heat required to raise the temperature of one pound of water one degree Fahrenheit at a specified temperature (as 39°F or 60°F) and equal to about 1055 joules

—called also Btu

Medical Definition

British thermal unit

noun

: the quantity of heat required to raise the temperature of one pound of water one degree Fahrenheit at a specified temperature (as 39°F)

—abbreviation Btu