What does one BTU measure?

One BTU, or British Thermal Unit, specifically measures the amount of heat necessary to raise the temperature of one pound of water by one degree Fahrenheit. This unit is essential in the HVAC field as it provides a standardized way to quantify energy and heat transfer, which is critical for heating and cooling systems.

Understanding this measurement is important for calculating the energy requirements for heating spaces, designing systems, and evaluating the efficiency of HVAC equipment. The other options refer to different concepts: cooling or electric energy production, which are not the definition of a BTU itself. Therefore, the definition of one BTU as the heat needed to raise the temperature of one pound of water one degree Fahrenheit is foundational to comprehending heat transfer and energy in HVAC applications.