Energy Intensity Calculator

Energy intensity is the amount of energy consumed per unit of output, floor area, or economic activity. For buildings, it is typically expressed as kBtu per square foot per year (kBtu/sq ft/yr). For industry, it is expressed as BTU per unit of product, per revenue dollar, or per employee. Lower energy intensity means more efficient use of energy.

The EPA Energy Star program benchmarks buildings using site energy intensity (kBtu/sq ft/yr) compared to a national median from the EIA Commercial Buildings Energy Consumption Survey (CBECS). A building scoring 75 or above on the EPA Energy Star 1-100 scale can earn Energy Star certification, meaning it performs in the top 25% of similar buildings nationally.

Site energy is the energy consumed at the building (as read from utility meters). Source energy includes the upstream energy required to produce and deliver site energy, accounting for generation and transmission losses. The EPA Portfolio Manager uses source energy for benchmarking because it reflects total environmental impact. For electricity, source energy is typically 3x site energy (due to ~33% average power plant efficiency).

From EIA CBECS 2018 data: Office buildings median ~75 kBtu/sq ft/yr; Retail stores median ~62 kBtu/sq ft/yr; Schools median ~56 kBtu/sq ft/yr; Warehouses median ~44 kBtu/sq ft/yr; Hotels median ~126 kBtu/sq ft/yr; Hospitals median ~350 kBtu/sq ft/yr. Energy Star certified buildings perform at or below approximately half these medians.

Industrial energy intensity is typically expressed as energy per unit of physical output (e.g., BTU per ton of steel, per barrel of oil, per pound of chemical). The DOE Advanced Manufacturing Office (AMO) tracks industrial energy intensity trends by sector and publishes manufacturing energy consumption data from the Manufacturing Energy Consumption Survey (MECS).