Problem: The benefits of LEED certifications are still hard to measure.
Solution: Build new branches at varying LEED levels to do real-world, cost-benefit analysis of the top-spec sites against those certified at lower LEED standards.
The jury's decidedly out on whether buildings constructed to LEED specifications are truly more efficient than those that aren't. That's because LEED buildings (those that have been certified "green" under the U.S. Green Building Council's Leadership in Energy and Environmental Design system) are always certified before any energy usage is actually measured that could conclusively prove that LEED works.
That lack of data has led Arvest Bank of Fayetteville, Ark., to test LEED concepts in its own branches. The bank is engaged in a multiyear cost-benefit analysis on LEED buildings to try to figure out the optimum spec to build to, weighing construction costs against savings on energy and facilities usage over time. Arvest is doing this by analyzing the energy consumption and building expenses across four branches built to different LEED-certified levels.
Arvest uses LEED solutions, like underground cisterns, to collect rainwater to flush toilets and irrigate landscaping at two of its gold-certified branches — one in Fayetteville and another in Springfield, Mo.
Yet Arvest is eschewing gold certification at two of its newest branches — one in Springfield, on which it broke ground June 6, and another under construction in Broken Arrow, Okla. — to instead aim for the lowest LEED level, known simply as "certified," to have a baseline means for comparison.
"After completing the four projects we'll evaluate all the materials, energy savings and costs, and then make a determination as to whether we would always try to hit LEED-certified gold or not, or always have rain harvesting systems," says Brent Vinson, site and planning coordinator at Arvest.
One of Arvest's rain harvesting cisterns recently made a bit of Arkansas history. Powering flushed toilets in the state with rainwater had typically required use of municipalities' filtration systems, or companies had to install an on-site filter for the intake water. "But for a small bank branch [the latter's] just not feasible," Vinson says. "So our engineer went to bat for us and lobbied the Department of Health and finally they allowed us to do it."
HSA Engineering, a consultant Arvest hired to support the project, successfully obtained an exemption from Arkansas' plumbing code from the state's Department of Health Review Board. After that, HSA successfully petitioned to make rainwater harvesting legal by pushing the state legislature to pass a bill in 2009 that encoded the practice into the state's plumbing guidelines, which were finalized in May of last year. Rainwater harvesting systems can be self-sustaining and cheap: Processing and treating water which need not be potable is considered expensive and wasteful by conservation proponents.
Arvest's Joyce Boulevard branch in Fayetteville became the first building of its type in Arkansas where a legal rainwater flushing system was used without a filter, Vinson says.
Arvest's newest branches are being built with other LEED-standard components, including low-volatile organic compounds that carry or emit fewer harmful chemicals than those typically contained in paint, glues, adhesives, carpet and millwork. Plus, the $11 billion-asset bank is recycling any construction materials that can be repurposed or reused. LED lights and heating, ventilation and air conditioning systems that power down or turn off depending on the time of day — or in some cases, when a room is vacant — are also included.
Another of Arvest's crucial LEED-certified components are bioswales, which are essentially modified ditches designed to remove pollutants and silt from rainwater. Instead of using the town's storm sewer and piping system in which the water ends up in a lake or stream, a bioswale channels and holds water on-site, letting it percolate into the ground to replenish the water table. The water is filtered typically through a layer of grass and then an engineered field of sand or some similar base below, which works to remove pollutants such as car oils.
Solar panels and geothermal cooling and heating, in which underground pipes feed ground air that naturally stays at a constant temperature, have been discussed, Vinson says. But business cases that would green-light such projects await development — solar is expensive and Arkansas' rocky ground makes channeling pipes tough. Regardless, Arvest's LEED efforts have so far garnered intangible marketing benefits. "People have actually come to the bank because they said they know we're doing this," Vinson says. "There have been enough of these comments that we know we're making a difference."