In 2010, in an effort to reduce fossil fuel dependence and CO2 emissions, Marc and Michele Sopher decided to install a geothermal heating system and a grid-tied photovoltaic array in their newly constructed home. The four-ton, ground source geothermal heat pump uses naturally stable underground temperatures to produce heat at relatively high efficiency, compared to resistive electric heating. But as a “renewable” technology this large heat pump is only as green as the considerable amount of electricity that is needed to power its pump and compressor. The Sophers were aware of this tradeoff while designing their home, and made the conscious decision to use solar electricity to help power the geothermal system. The home was designed to be near net zero. It also incorporates efficient building materials that are non-toxic and of sustainable origin. Insulation levels are R40 in the walls and R60 in the ceiling to ensure minimal heat loss during the cold New England winters.