Don't Forget the EE in Green
Standards for green consider a number of factors, including recycled and renewable materials, water savings, indoor air quality, siting and energy efficiency (EE). Yet, upon closer look, many buildings touted as green may be no more—and perhaps even less—energy efficient than their browner neighbors. The terms ‘sustainable’ and ‘high-performance’ offer no stronger guarantees of energy efficiency for buildings.
Buzz…buzz…buzz. That’s the sound of energy and enthusiasm around the green building movement. We’re all talking about it—the desire for environmentally friendly buildings where we live, work and play. But what does it really mean when a building is green?
Standards for green consider a number of factors, including recycled and renewable materials, water savings, indoor air quality, siting and energy efficiency (EE). Yet, upon closer look, many buildings touted as green may be no more—and perhaps even less—energy efficient than their browner neighbors. The terms‘sustainable’ and ‘high-performance’ offer no stronger guarantees of energy efficiency for buildings.
Why are green buildings not always energy-efficient buildings?There are several reasons, including the way green rating systems treat and define efficiency, as well as changes that inevitably occur from the design stage to building operation. Some of the prevailing methods for defining green, sustainable and high performance buildings allow efficiency to be traded for other environmental attributes, rather than making top efficiency a required feature. Adding to the confusion, even those buildings that appear to be efficient may in fact be designed to use more energy than the average building in operation today. This paradox is the result of defining efficiency based solely on a‘better than energy code’ approach that compares a building designed to exceed the local energy code with the same building designed to just meet code. Using this approach, a building design can look much more efficient than it would with basic, code-compliant features, but still perform poorly against similar buildings in the market.
Commercial buildings are responsible for 17% of the total energy consumed as well as 17% of greenhouse gasses emitted just from the energy use of the building.1 [epa1] . We know there are significant opportunities to reduce energy use. In fact, the most efficient commercial buildings operate with 10 times less energy per square foot than the least efficient. Even more surprising, many new buildings use substantially more energy per square foot than older buildings. Buildings that are energy-efficient are likely to have better indoor air quality, as well as greater satisfaction and comfort for occupants.
Decisions made during design and construction set the course for lifetime energy use—and the associated cost and environmental impact—of buildings. For a typical office building, energy represents 30% of variable costs, and the single largest controllable operating cost. Over the life of the building, energy cost is a staggering sum. The difference in energy costs between a typical building and an efficient building can be several million dollars. For example, buildings that have achieved the ENERGY STAR label for superior energy efficiency use 40% less energy than average buildings. A recent study found that, conservatively, “[t]hese savings are equivalent to about $0.50 per square foot per year in lower energy costs. For a 100,000-sq.-ft. office building, this translates to an annual energy bill that is $50,000 below that of an average building.”2Over the building’s 40-year lifetime, the savings grow to $2 million. And these are just the direct financial benefits. Evidence is growing that a more energy-efficient building is also a more valuable building. For example, USAA Realty increased the market value of a property in California by $1.5 million as a result of energy-efficiency improvements, according to the sales broker.3
The environmental benefits of energy efficiency are just as impressive—and important—as the financial benefits. With less energy needed to run buildings, power plants emit less greenhouse gases.
To deliver buildings that help the environment and the bottom line, start by setting clear energy-efficiency goals based on how real buildings perform and verify actual performance using the same market-based data as part of your overall efforts to be green. Designers, architects and building owners can do just that with the help of ENERGY STAR, which provides energy targets for specific types of buildings, grounded in real energy data from a large sample of existing buildings.
For many types of new buildings, ENERGY STAR’s Target Finder provides an energy performance target of 1 to 100 that accounts for expected differences in energy use due to business activity, such as hours of operation and number of computers, as well as weather variations. The target is derived from statistical analysis of the DOE’s Commercial Building Energy Consumption Survey. A new building should be designed for top energy efficiency, which translates to a target of at least 75, the level at which a building design qualifies for the “Designed to Earn the ENERGY STAR” recognition. Buildings designed to achieve a target of 90 would use 50% less energy than the average building, meeting AIA’s 2010 target. Of course, blueprints don’t save money or reduce emissions—so verifying building performance once it is operating is a critical step.
For existing buildings, ENERGY STAR’s Portfolio Manager uses the same approach as Target Finder to rate actual energy performance based on 12 months of energy bills. Buildings rating 75 or higher may qualify for the ENERGY STAR and are in the top 25% of buildings across the country.
There are signs that this new approach is gaining acceptance. At the end of 2006, more than 3,200 buildings had earned the ENERGY STAR. More than 30,000 buildings, representing more than 5 billion sq. ft. of commercial building space have been rated, and more than 40 organizations have demonstrated portfolio-wide improvements of 10% or more. On a quarterly basis, this column will help to bring proven practice to inspire engineers and building owners to consider energy-efficient measures for new and operational buildings and empower them with ENERGY STAR tools and information, and resources from other programs and institutions, to begin saving energy and money while benefiting the environment.
About the author
Jean Lupinacci is the director of the Commercial and Industrial Branch in the Climate Protection Partnerships Division at EPA. Her responsibilities include managing the ENERGY STAR program to help businesses improve the energy performance of their buildings. An economist, she has been with EPA for over 20 years. She can be reached at firstname.lastname@example.org . For more information about ENERGY STAR please visit www.energystar.gov .
1.“Inventory of US Greenhouse Gas Emissions and Sinks: 1990-2004,” USEPA #430-R-06-002, April 2006.
3.Communication with Brenna S. Walraven, Executive Director, National Property Management, USAA Realty Co.