How is the quantity of heat expressed in HVAC terminology?

In HVAC terminology, the quantity of heat is commonly expressed in British Thermal Units (BTUs). A BTU is defined as the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit. This unit is particularly relevant in heating, ventilation, and air conditioning systems because it provides a clear and practical way to quantify energy transfer and thermal effects in residential and commercial buildings.

Understanding BTUs is essential for assessing the heating and cooling capacity of HVAC equipment, allowing professionals to size systems appropriately for different spaces. While calories, Joules, and Watts are also units related to energy and heat, BTUs are the standard used in the North American HVAC industry, making it the most relevant choice for expressing heat in this context.