EPA Releases Updated ENERGY STAR Score Model for U.S. Office Properties
In August 2018, the EPA updated the ENERGY STAR score model using recent market data to account for changes in market trends and performance. The data collected indicated that energy use and business practices in U.S. commercial buildings have changed since the EPA last updated the ENERGY STAR score model using 2003 data. To assess the updated score model, the EPA gathered information from various commercial buildings across the country. From the properties’ feedback, the EPA found that buildings located in colder regions observed greater score reductions. This finding highlighted the emphasis to include heating degree days (HDD) in the scoring model, which the previous one did not. The EPA found that an adjustment was needed to account for energy use for heating. By reintroducing HDD in the scoring process, office buildings in all climates saw more equitable scores.
On July 22, 2019, office building scores, with an adjustment for HDD, will be available in Portfolio Manager. Users may see score increases for properties located in colder climates, but no buildings will see a decrease. Make sure to download current scores before July 21, 2019 (Portfolio Manager will not be available that day for the release of the updated score model), to compare scores against the revised model. The download can be found under “my portfolio tab”, and click “download your entire portfolio to excel” for your current scores.
ENERGY STAR score model provides a comparative national benchmark of a building’s energy use to other buildings. The August 2018 scoring model was created using data collected from the Energy Information Administration (EIA) 2012 Commercial Building Energy Consumption Survey (CBECS). The table below summarizes changes in data between 2003 and 2012. The estimated number of buildings increased by 23%, while the energy use decreased by 16% in terms of site energy use intensity (EUI), and 12% in terms of source EUI.
The EPA concluded that the 2018 scoring model accurately evaluates the energy performance of office buildings, except for heating energy. After soliciting feedback from portfolios across the US, it was found that buildings in colder climates on average scored lower than their peers in warmer climates. They found that the model could not account for year to year variation in heating energy because it did not include an HDD variable. With the re-introduction of HDD to the scoring process, the revised model will be able to deliver more appropriate energy performance metrics for office buildings. Other factors that influence a building’s score includethe fuel mix and activity level of a building. To account for these impacts, adjustments were made so that the factors included are now consistent with those in the previous model. The table below further summarizes the adjustments.
To accurately include HDD to the scoring model, the EPA used the Department of Energy’s commercial reference buildings report (U.S. Department of Energy Commercial Reference Building Models of the National Building Stock). The resulting factor for estimating heating energy is 0.0047 kBtu/square foot/HDD. This estimated factor is then added to the normalized mean resulting from the current model. This process is further explained in the diagram below. Using this approach, the average score and the percent of buildings scoring 75 or greater increased.
The tables below further highlight the positive relationship between HHD’s in colder regions and the building’s ENERGY STAR score. A building in New York may see a score increase of 3 on the low end or a score increase of 7 on the high end. It is important to note, that no scores decreased with the HDD adjustment.
The EPA further tested the revised score model, and concluded the model produces balanced scores for office buildings of varying sizes and characteristics. Certification re-opens on July 31st, so in order to apply for certification in 2019, you must apply for certification for 2018. To receive certification, you need a score of 75 or higher, and need 12 months of historical data. Once you have all the necessary information, you have until December 31, 2019, to apply. (Certification Information) The next energy score update will occur in four to five years, using 2018 data.
Amid these changes, it is important to work with a company that understands how ENERGY STAR scores are calculated and can help you explain any changes to your score. Our watchwire platform integrates with ENERGY STAR Portfolio Manager. Learn more about how watchwire automates Portfolio Manager updates, simplifies your trend and variance reporting, and optimizes your facilities through peak load management, real-time monitoring, and strategic energy procurement.
July 18, 2019
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