This 20,000-square-foot addition to the Frank Lloyd Wright–designed National Historic Landmark Meeting House includes a 500-seat auditorium, office and meeting space, a kitchen, fellowship space, and music rehearsal spaces. It is LEED Gold– certified.

Although the new auditorium triples seating capacity on site, parking was reduced from 127 spaces to 96 spaces and bicycle storage spaces were created. Two bus stops are within a quarter-mile of the site.

The new building is 40 percent more efficient than a comparable base case facility. The heating and cooling systems were decoupled from ventilation needs, allowing more fresh air to be provided at a reduced cost. Thermal loads are transferred via radiant floor heating and cooling. Interior courtyards provide daylight, and a narrow building plan allows 91 percent of regularly occupied areas to be daylit.

Dual-flush toilets, waterless urinals, and low-flow faucets have reduced building water use by 35 percent over comparable facilities, and nearly all stormwater is retained on site. Stormwater is absorbed by a vegetated roof and once it is saturated, runoff is directed to an underground filtration chamber. Overflow is then piped to two rain gardens, while stormwater that falls onto impervious roofing is now directed to a landscaped courtyard. Runoff from impervious parking surfaces is directed through a series of bioswales.

By the numbers:

Building gross floor area: 24,327 square feet
Number of occupants: 2 (plus 658 visitors)
Percent of the building that is daylight: 76
Percent of the building that can be ventilated or cooled with operable windows: 73
Total water used, indoors and outdoors: 203,100 gallons per year
Calculated annual potable water use: 8.35 gallons per square foot per year
Total energy (MBtu per yr): 810
EPA performance rating: 42
Percent total energy savings: 41
LEED rating: Gold, LEED-NC v.2.2

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