- Roof produced a 10 percent decrease in building energy use over the winter months.
- The temperature on the green roof on the hottest summer days can be as much as 59 degrees cooler than conventional roofs on neighboring buildings.
- During a 10–month monitoring period, ASLA’s green roof prevented 27,500 gallons of stormwater — nearly 78 percent of all precipitation hitting the roof — from flowing into D.C.’s overburdened sewer and stormwater system.
- Water quality testing shows that the water runoff contains fewer pollutants than typical water runoff. Most significantly, the roof is reducing the amount of nitrogen entering the watershed.
- Except during repeated heavy rains, the roof only creates runoff during rainfalls of more than one inch.
Synopsis of Performance
Sustainability with Style: The ASLA Headquarters Green Roof, by Nancy Somerville, Hon. ASLA and Chistopher Counts, ASLA