BPI Building Analyst Practice Test 2025 - Free Building Analyst Practice Questions and Study Guide

AFUE, or Annual Fuel Utilization Efficiency, measures the efficiency of a furnace or boiler in converting fuel to usable heat over the course of a year. It is a critical metric for understanding how effectively these heating systems operate. The key point about AFUE is that it only accounts for the heat produced by the unit itself and does not factor in the losses that may occur during the distribution of that heat throughout a building.

Distribution losses occur as heated air or water travels through ductwork or pipes to reach different areas of a home or building. These losses can be significant, especially in older buildings with poor insulation or leaking ducts, but AFUE does not take them into account. Instead, AFUE focuses solely on the efficiency of the combustion process and the heat generated in relation to the fuel consumed.

As a result, when evaluating a heating system's overall effectiveness, it’s important to consider both AFUE and distribution efficiencies to truly understand the system's performance in real-world conditions.