Energy Star changes
Energy Star has undergone a significant revision effective October 2007.
Judith M. Peters, mechanical engineer, LKPB Engineers Inc., Saint Paul, Minn. -- Consulting-Specifying Engineer, 2/15/2008 12:20:00 PM
Energy Star, the national energy performance rating system sponsored by the U.S. Environmental Protection Agency (EPA), has undergone a significant revision effective October 2007. Commercial building owners and property managers who previously struggled with a low Energy Star score might be pleasantly surprised by recent changes in the rating calculations.
Prior to the October 2007 revision, LKPB Engineers Inc. (LKPB) noticed that buildings with attached parking garages received lower ratings than their counterparts without parking garages. Further investigation revealed that the presence of a parking garage resulted in a significant deterioration in a building’s Energy Star rating. For the same inputted energy, larger square footage (building plus parking ramp) resulted in a lower rating than just the building alone.
When brought to the attention of the EPA technical staff, they reviewed their rating system and promised to resolve the issue in their October 2007 revision. From LKPB’s preliminary test cases, it appears that the problem has been corrected. As one example, September calculations on a Bloomington, Minn., office tower resulted in an Energy Star rating of 65. Recalculations in December resulted in an Energy Star rating of 85. The tower previously fell short of the 75 threshold, but now qualifies for the Energy Star designation.
In other examples, other Minneapolis-area buildings are now Energy Star rated:
* Normandale Lakes Office Park, Bloomington, Minn., had two buildings that were affected by the change: The 8400 tower went from a rating of 54 to 76; the 8500 tower went from 63 to 92.
* The Minnesota Center, another office tower in Bloomington, previously did not qualify for Energy Star, and now has a rating of 87.
* The Colonnade, a tower located in Golden Valley, Minn., previously had a rating of 66 and recently qualified for Energy Star with a rating of 93.
Building owners and property managers with commercial buildings that have attached parking garages should be encouraged to resubmit their Energy Star data as soon as possible to see if their rating improves.
The Energy Star rating system continues to be based on data from the Commercial Building Energy Consumption Survey (CBECS). This survey sample of more than 6,000 buildings across the United States is conducted every four years by the United States Department of Energy’s Energy Information Administration. The survey collects complete billing data and operational details for a wide variety of commercial building types.
A common misconception is that Energy Star performance ratings are based on information from other buildings that apply for the Energy Star rating through its on-line Portfolio Manager. The rating is actually based solely on the data collected by the CBECS and the aforementioned formula.
