Architectural Heritage Foundation, in partnership with Historic New England and the Trustees of Reservations, will complete Deep Energy Retrofits at three historic properties in the Commonwealth: The Lyman Estate in Waltham, the Bullit Reservation in Conway/Ashfield, and the Appleton Farms Center for Agriculture and the Environment in Ipswich. Each of the Deep Energy Retrofits takes a different approach, and will provide valuable information for future retrofits of historic properties. Notable features include a historically sensitive retrofit to the Lyman Estate that preserves historic values of the property, efforts to make the Bullit Reservation a certified “passive house” that uses little to no fossil fuel energy, and a comprehensive building envelope treatment at Appleton Farms including exterior super-insulation, air source heat pumps and solar thermal hot water systems.