In which unit is heat measured?

Heat is commonly measured in several units, one of which is the British thermal unit (BTU). The BTU is a traditional unit of measurement that describes the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit at a constant pressure. It is widely used in the field of heating, ventilation, and air conditioning (HVAC), as well as in other applications involving thermodynamic systems.

While other units such as joules, calories, and kilojoules are also valid measures of heat energy, the specificity of the BTU in certain applications makes it a key unit in evaluating heat transfer in practical situations, particularly in the United States. This relevance is why BTUs are often emphasized in discussions about heating efficiency and energy consumption. The other units mentioned are generally used in more scientific contexts or for different applications but do not match the practical usage of BTU in many heating-related scenarios.