The Environmental Protection Agency’s EPA’s 1 - 100 ENERGY STAR score is an external benchmark for assessing the performance of commercial buildings.
The ENERGY STAR score, expressed as a number on a simple 1 - 100 scale, rates performance on a percentile basis: buildings with a score of 50 perform better than 50% of their peers; buildings earning a score of 75 or higher are in the top quartile of energy performance.
First introduced in 1999, the score has been adopted by leading organizations across the United States because it offers a simple way to evaluate measured energy use, prioritize investments, and communicate relative performance across a portfolio of buildings.
Recognizing the widespread adoption of the ENERGY STAR score in the commercial marketplace, EPA continually reviews and updates the technical approach to ensure accurate, equitable, and statistically robust scores. The overall objectives of the ENERGY STAR score are to:
Evaluate energy performance for the whole building
Reflect actual metered energy consumption
Equitably account for different energy sources
Normalize for building activity
Provide a peer group comparison
Once developed, the ENERGY STAR score is programmed into EPA’s online measurement and tracking tool, ENERGY STAR Portfolio Manager®. The following steps are used to compute the score for an individual property:
Enter data into Portfolio Manager
Compute actual source energy use intensity
Compute the predicted source energy use intensity
Compute an efficiency ratio comparing the actual use with the predicted use
Assign a score based on how the ratio compares with the national distribution
Facility Management Objectives
EPA has identified the following objectives for a successful energy performance metric in California facilities:
1. Evaluate energy performance for the whole building. Rather than examining specific pieces of equipment within a building, a whole building metric accounts for the interactions among the various system components. For example, a particular HVAC system may be designed with efficient components, but if it is over-sized relative to the actual heating and cooling loads it will not perform efficiently. A robust analysis must account for energy use of the whole building.
2. Reflect actual metered energy use. The ENERGY STAR score must reflect the actual metered or billed energy consumption at a property. It cannot be based on predicted or simulated energy use, as simulations often fail to account for both the impact of building operation and maintenance patterns and the interactions among building systems.
3. Equitably account for different energy sources. Source energy accounts for both energy
consumed at the site as well as energy used in generation and transmission. This approach is the most equitable for assessing properties with different fuel mixes and buildings with onsite power generation systems. In addition, source energy is more reflective of energy costs and GHG emissions.
4. Normalize for building activity. The intent of the ENERGY STAR score is to provide a fair assessment of energy performance, taking into account operational conditions required for the business activities within the building. Normalization requires adjustments to account for factors such as weather, operating hours, and the number of workers.
5. Provide a peer group comparison. A peer group comparison enables building owners and operators to track not only their improvement over time, but also how they stack up when compared to others with the same primary business function (e.g., retail store).
Computing Your Score
To receive an ENERGY STAR score in Portfolio Manager, you must enter 12 full calendar months of energy data for all energy types, in addition to complete data on property use details such as hours of operation and workers. To determine the score, Portfolio Manager will compute both the actual source energy use intensity (EUI) and the predicted source EUI based on these inputs.
The ratio of actual source EUI to predicted source EUI is the efficiency ratio, which can be mapped through a lookup table to determine the 1 - 100 ENERGY STAR score. A score of 75 indicates that the building performs better than 75% of its peers and this score or better should be your minimum objective.
Need help in setting up your facility's ENERGY STAR Portfolio Manager and evaluating your score and potential savings? If the answer is yes, please contact Corey Lee Wilson at firstname.lastname@example.org or call (951) 415-3002 for more information and learn how little it costs for set-up and implementation.