BPI Multifamily Building Operator (MFBO) Practice Exam

Energy use index in this context measures how much energy is used for heating relative to both the building’s size and the climate. It’s defined as the annual energy consumption in Btu, divided by the building’s floor area in square feet, and then divided again by Heating Degree Days. This yields a value in Btu per square foot per Heating Degree Day, showing how much energy is used to heat each square foot for each degree of cold experienced over the year. This is why the right choice uses Btu per square foot per Heating Degree Day. It’s the only option that normalizes energy use to both the building size and the climate’s heating demand. The other options either fail to normalize by degree days, use the wrong unit (Watt-hours per year or kWh per square meter), or apply Cooling Degree Days instead of Heating Degree Days, which would reflect cooling rather than heating energy.