[This article was originally published on Historecycle and is reprinted with permission. Historecycle was founded to showcase historic building renovations where green features are integrated into the redesign. Unity Temple Restoration Foundation is the secular, non-profit organization that led the fundraising efforts to complete this project.]

Unity Temple, a world-famous Unitarian church, recently underwent a full-scale makeover. The 1908 structure, a National Historic Landmark designed by Frank Lloyd Wright, was closed for repairs in 2015. Two years later, the 8000-square-foot Temple emerged from its temporary plastic cocoon, a painstakingly restored gem that balances the modern with the historic, and the aesthetic with the sustainable. Now the faithful pass through its (hopefully) leakproof concrete shell to an inner sanctum that is energy-efficient and climate-controlled.

The heart of the restoration is the geothermal system, whose arteries are a series of interconnecting fluid-filled pipes, extending 500 feet deep in nine wells (boreholes) in the church’s front lawn. The pipes serve as a conduit between the building interior and the earth’s steady temperatures, providing air-conditioning in summer and heat in winter.

​Other HVAC improvements include a ventilation system that supplies air only when required and captures waste heat from exhaust air. Insulation added to each of the Temple’s 16 flat roof surfaces also keeps the formerly drafty sanctuary from losing heat.

Building materials and components were recycled and retained wherever possible. Instead of tossing old shotcrete (spray-on concrete) after blasting it off the exterior, it was mixed into the aggregate used to mend outdoor wall cracks. Inside, Wright’s trademark art glass and oak trim were removed piece by piece, inventoried, shipped off site for cleaning and repair, and then reinstalled. Churchgoers sit on refurbished pews. Overhead, new insulated-glass skylights supplement the existing ones; and original lamps now contain LED lights regulated by dimmer switches.

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