A BTU is defined as which of the following?

• A. British Thermal Unit
• B. Barometric Temperature Unit
• C. Basic Thermal Unit
• D. Binary Thermal Unit

Answer: (A)

BTU is a unit of heat energy used in many engineering and HVAC contexts. It stands for British Thermal Unit and defines the amount of heat needed to raise the temperature of 1 pound of water by 1 degree Fahrenheit at standard atmospheric pressure, which is about 1,055 joules. In practice, HVAC ratings use BTU and BTU per hour to express how much heat a system can add or remove per hour (for example, 12,000 BTU/h equals one ton of cooling). The other phrases listed aren’t recognized units for heat energy, so they don’t describe what a BTU measures.