Partially earth-sheltered, this house was designed and built from from the ground up by SunPower. It incorporates sustainable design techniques such as passive and active solar, including: house orientation to maximize solar gain; a 3 kW PV system; solar water-heating system; and a solar radiant heated floor.  The house uses materials and design techniques such as: soy-based super-insulation and blown-in cellulose insulation; air-sealing; high-performance windows; timber framing; and Sip’s panels. These elements were combined with antique detailing and salvaged and eco-friendly materials to replicate the other historic buildings on the property while creating a highly efficient and cozy guest cottage.  This super-energy efficient space used less than $200 in energy costs over its first year.