A British Thermal Unit (BTU) is a traditional unit of heat energy. It is defined as the amount of energy required to raise the temperature of one pound of water by one degree Fahrenheit at sea level.
What is a Joule (J)?
The joule (J) is the SI unit of energy, work, or amount of heat. One joule equals the energy transferred when a force of one newton acts over a distance of one meter.
Practical applications
Heating, ventilation, and air‑conditioning (HVAC) systems often rate capacity in BTU/h.
Electrical and mechanical engineering calculations use joules for precise energy budgeting.
Fuel‑energy content, refrigeration cycles, and thermodynamic analyses frequently require conversion between BTU and joule.
The exact conversion factor is \\ (1\\ \text{BTU}=1055.05585\\ \text{J}\\).
British Thermal Unit to Joule Conversion Reference Table
British Thermal Unit (BTU)
Joule (J)
0.1
105.5056
0.5
527.5279
1.0
1055.0558
2.0
2110.1117
5.0
5275.2792
10.0
10550.5585
20.0
21101.117
50.0
52752.7925
100.0
105505.585
500.0
527527.925
1000.0
1.0551e+06
Conversion Example: 10 BTU to Joules
Step‑by‑step:
Identify the conversion factor: \\ (1\\ \text{BTU}=1055.05585\\ \text{J}\\).
One BTU is the energy needed to raise the temperature of one pound of water by one degree Fahrenheit. In practical terms it is roughly the heat released by burning a small match or the energy required to heat a cup of coffee by about 10 °F.
In SI units this equals \(1\ \text{BTU}=1055.05585\ \text{J}\).
The factor 1055.05585 J comes from the precise definition of the calorie (the amount of energy to raise 1 kg of water by 1 °C) and the exact relationship between imperial and metric units. Rounding to 1055 J would introduce a small but measurable error in high‑precision engineering calculations.
"On fait la science avec des faits, comme on fait une maison avec des pierres ; mais une accumulation de faits n'est pas plus une science qu'un tas de pierres n'est une maison." "Science is built up of facts, as a house is built of stones; but an accumulation of facts is no more a science than a heap of stones is a house." — Henri Poincaré (French Mathematician, Theoretical Physicist & Mining Engineer)