A colleague asked a good question the other day: “Which is more energy efficient– an ENERGY STAR Labeled or a LEED Certified building?” Although there’s no simple answer, it’s worthwhile to look at the two most highly recognized designations for green buildings.
ENERGY STAR is the EPA’s energy performance benchmarking and recognition program. Easy and free to use, ENERGY STAR compares a building’s energy data to that of similar facilities to provide a benchmark score of 1-100. It is universally considered an accurate indication of a building’s energy performance based on location, size, occupancy density, computer density, space use and hours of operation.
ENERGY STAR is continually enhanced as a performance measurement tool, including the recent addition of water usage information. It also provides a year-over-year comparison normalized for variables such as weather. And greenhouse gas emissions are automatically calculated.
The purpose is to allow owners and managers to benchmark their buildings’ performance and be recognized for their performance, to encourage environmental enhancements in line with EPA’s mission. Recognition comes in several forms: A building with 75 or higher ratings may be eligible for an ENERGY STAR Label, while an owner or manager that achieves, portfolio-wide improvements of 10 percent or more may be recognized as ENERGY STAR Partner or Partner of the Year. Achieving an average rating of 75 or better portfolio-wide may result in recognition as a Top Performer.
Leadership in Energy and Environmental Design (LEED) is the leading international program for recognizing sustainable buildings—not just energy but water efficiency, indoor air quality, innovative design, use of green materials and resources, sustainable sites and other evidence that a building is maintained and operated in an environmentally sustainable way. Unlike ENERGY STAR, LEED certification costs money, prompting some owners to forego certification even as they follow LEED principles.
To validate various sustainability metrics, LEED relies on recognized standards from organizations like ASHRAE and ASTM. Not surprisingly, ENERGY STAR is the core tool for measuring energy performance. In fact, a building must have an ENERGY STAR score of 69 or higher to qualify for LEED, and higher scores are worth more points toward certification.
One study of LEED found that many certified buildings were not energy efficient. At the time of the study, most certified buildings were New Construction (NC) and may not have performed in practice the way they were designed. A building certified under the current standard for existing buildings, Operations & Maintenance (OM), must have a high ENERGY STAR score, at least in every year it is certified or recertified.
So, back to the original question: LEED is typically, but not always, an indication of superior energy performance, and of a sustainable building overall; while an ENERGY STAR label is always the mark of superior energy performance, but says little about sustainability beyond energy. And higher levels of LEED certification often, but not always, are more energy efficient than lower levels, while a higher ENERGY STAR is always superior to a lower score.