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Coastal Maine Botanical Gardens Bosarge Family Education Center

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Project Name

Coastal Maine Botanical Gardens Bosarge Family Education Center

Project Status


Year Completed



8,200 sq. feet


  • Thornton Tomasetti

Certifications and Designations

Project Description

The 8,200 SF LEED Platinum Coastal Maine Botanical Gardens Bosarge Family Education Center in Boothbay, Maine has been awarded the 2013 Zero Net Energy Building Award by the Northeast Sustainable Energy Association (NESEA). Thornton Tomasetti, the international engineering firm, served as the project’s green building consultant.

The Center is one out of a handful of net zero non-residential buildings in all of New England, and is the second commercial LEED Platinum building in Maine. The Net Zero Energy Building Award is NESEA’s annual search for the best building in the Northeast that captures as much energy as it consumes. To achieve this rating, NESEA requires the winning building to be one that offers not only efficiency, but also comfort, affordability, reliability and elegance.

The walls and roof that make up the building envelope are at least a foot thick, achieving an impressive efficiency rating of R40 in the walls and R60 in the roof. Special triple-glazed windows, among the most efficient that can be bought in the U.S, provide passive solar gain in the winter, while keeping out the heat in the summer. In addition, a recent energy audit of air leakage concluded that air infiltration at the facility is by far the lowest in the state.

To produce the energy load required to achieve Net Zero, the building is equipped with 135 photovoltaic panels on the south side of the roof, plus an additional 102-panel array on the ground. Payback from the solar system is estimated at 10 years.

The design was led by a collaboration between Portland-based Scott Simons Architects, which has been recognized nationally for innovative design, and Maclay Architects from Waitsfield, Vt. known for their sustainable, net zero expertise. In addition, Allied Engineering, also of Portland, collaborated with Energy Balance of Montpelier, Vt. to design and engineer the mechanical and electrical systems, which include a massive array of on-site solar photovoltaic electricity generation capable of generating 55,184 kilowatt hours. H. P. Cummings of Winthrop, Maine was the construction manager on the project. Becker Structural Engineers provided structural design services for the project. Bensonwood, of Walpole, New Hampshire, builders of high performance houses and commercial structures, produced and installed the super-insulated, tightly-sealed building shell.

The public can track the building's energy use and production at

Thornton Tomasetti
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