How the Rating System Works

The national energy performance rating is a type of external benchmark that helps energy managers assess how efficiently their buildings use energy, relative to similar buildings nationwide. The rating system’s 1–100 scale allows everyone to quickly understand how a building is performing — a rating of 50 indicates average energy performance, while a rating of 75 or better indicates top performance.

EPA, in conjunction with stakeholders, developed the energy rating as a screening tool; it does not by itself explain why a building performs a certain way, or how to change the building’s performance. It does, however, help organizations assess performance and identify those buildings that offer the best opportunities for improvement and recognition.

How is the rating calculated?

Based on the information you entered about your building, such as its size, location, number of occupants, number of PCs, etc., the rating system estimates how much energy the building would use if it were the best performing, the worst performing, and every level in between. The system then compares the actual energy data you entered to the estimate to determine where your building ranks relative to its peers.

All of the calculations are based on source energy. The use of source energy is the most equitable way to compare building energy performance, and also correlates best with environmental impact and energy cost.

To estimate how much energy your building would use at each level of performance, EPA conducts statistical analysis on the data gathered by the Department of Energy’s Energy Information Administration during its quadrennial Commercial Building Energy Consumption Survey (CBECS). For each type of building for which EPA offers a rating, EPA goes through a rigorous process that involves:

• Ensuring the quality and quantity of the data will support a rating
• Creating a statistical model that correlates the energy data to the operational characteristics for each building to identify the key drivers of energy use
• Testing the model with real buildings

Please refer to Model Technical Descriptions for more information on the specific data analysis for each available building type.