Built into an existing neighborhood forty-five minutes northwest of Boston, the Harvard Colonial features non-traditional building components behind its traditional façade. A combination of cavity and rigid insulation in the wall, roof and foundation assemblies and high performance windows make up the thermal enclosure. To increase the home's durability, the cladding is back-vented, preventing water from remaining in the assembly should the wall get wet. A closed loop ground source heat pump provides the home's heating and cooling while continuous ventilation is provided by a controlled outside air duct. Open web floor trusses provide a convenient location for the ductwork, which distributes conditioned air to the first, second and third levels of the 5,000 square foot home. All of these components combine to create a home that uses 30% less energy for heating, cooling and hot water than a 1996 code built home.