How are oil furnace capacities expressed?

Oil furnace capacities are typically expressed in terms of output. This refers to the amount of heat energy produced by the furnace while it is operating. The output capacity is measured in BTUs (British Thermal Units) per hour, which indicates how much heat the system can deliver to space effectively.

By focusing on output, professionals can evaluate the performance of the oil furnace based on the heat it generates for residential or commercial heating needs. Understanding the output is crucial for determining whether a furnace is appropriately sized for a building's heating requirements.

While input capacity, which is also expressed in BTUs, represents the total energy consumed by the furnace to operate, the key metric for assessing a furnace's actual heating capability is its output. Thus, output is the most relevant measure when discussing furnace capacities in practical applications.