What does "bonnet capacity" refer to in a furnace?

Bonnet capacity refers to the amount of heat output that a furnace can provide, measured in BTUs (British Thermal Units). This term is commonly used to indicate the effective heating capability of the furnace as it relates to its design and operational performance. The furnace's output BTUs represent the actual thermal energy that the unit delivers into the heating space after accounting for any losses in the system.

Understanding bonnet capacity is essential for selecting the right size of the furnace for a specific application, ensuring it can adequately meet the heating demands of the space it serves. Properly matching furnace output with heating requirements optimizes energy efficiency and comfort, avoiding both under-heating and over-heating scenarios within a building.