In what unit of heat is an oil furnace capacity expressed?

The capacity of an oil furnace is expressed in BTU/H, which stands for British Thermal Units per hour. BTU is a traditional unit of heat energy used primarily in the United States for measuring the heat content in fuels and the heating capacity of appliances. This unit quantifies the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit.

Using BTU/H makes it easier for HVAC professionals to compare and evaluate the heating capabilities of different oil furnaces. It also allows for more straightforward calculations regarding energy consumption and efficiency since it relates directly to thermal outputs in the context of heating systems.

The other units mentioned, such as watts and kilowatts, are more commonly associated with electrical power and are used in other contexts. Joules, although a valid measurement of energy, is not typically used in the context of heating systems for expressing furnace capacity. Therefore, BTU/H is the most relevant and widely accepted unit for this purpose within the HVAC industry.