The U.S. Green Building Council created the LEED (Leadership in Energy and Environmental Design) program more than a decade ago to promote environmentally responsible buildings that are also healthy, comfortable places to live and work. While we have seen an emphasis on new construction (the majority of LEED registered and certified buildings pursue LEED for New Construction or LEED version 3 - Green Building Design & Construction), LEED is not just for new construction projects. In fact, there are more than 45 million existing buildings in the U.S. alone, comprising billions of square feet of existing building stock. As such, a new trend is moving towards existing buildings seeking LEED for Existing Buildings: Operations & Maintenance (LEED-EB:O&M), or the new LEED version 3 - Green Building Operations & Maintenance (O&M).

Our current economic situation has helped push building owners and managers into thinking more about improving their existing buildings rather than investing in new construction projects. Still, there are questions as to whether seeking LEED certification for an existing building is a cost-effective option. As with LEED for New Construction, there are critics who claim costs to implement are too high, and that measurable benefits are minimal. In the case of LEED O&M, that simply isn't true.

LEED-O&M focuses on helping owners and managers solve building problems, improve building performance and maintain and improve performance over time. LEED-certified buildings in this category have demonstrated financial savings for both building owners and tenants. Recent studies conducted by the New Buildings Institute and CoStar found that LEED buildings rent for more, sell for more and have higher occupancy rates. The study indicates that LEED-certified buildings command rent premiums of $11.24 per square foot over their non-LEED counterparts and boast a 3.8 percent higher occupancy rate. The same Costar study also found that LEED buildings use 25-30% less energy, on average, than non-certified buildings. As such, a LEED-O&M certified building translates to lower operating costs and utility bills for the tenants.

For those concerned about the return on investment with respect to efficiency savings, LEED-O&M emphasizes energy and water efficiency. The credits are weighted accordingly to prioritize those that pertain to climate change and greenhouse gas emissions. Ongoing building commissioning and sub-metering also is emphasized to demonstrate actual energy performance levels resulting from O&M retrofits. A Lawrence Berkeley Lab study of 65 existing buildings found that commissioning has an average 0.7 year payback on energy savings alone, with the worst performer experiencing payback after just 2.8 years and the best at 0.2 years. Providing a localized perspective, the City of Atlanta realized a savings of $100,000 following an audit we performed in one city-owned facility.

In addition, LEED-O&M features performance-based credits that reward measured results such as a demonstrated reduction in commuting trips, rather than prescriptive measures like incorporating bicycle storage and changing rooms into a building's design. With an emphasis on performance-based credits that implement required plans and policies, energy and water metering, and on-going commissioning, the building owner will save money.

Creating sustainable environments, at whatever stage of a building's life, is today's business reality. The cost to implement is returned through long-term savings. Consumers are more educated about the benefits and are demanding healthier environments. In addition, governments are assisting the push to change with new mandates and regulations. The resulting progress in this area will bring about both environmental and economic rewards.

Lauren Gloster is a Senior Sustainability Consultant with Energy Ace, specializing in LEED Administration and Consulting. She has been involved with more than 20 LEED projects, serving as the LEED Administrator, Energy Modeling Coordinator and/or Commissioning Coordinator.