S+H President Doug Hanna took an important step towards reducing carbon footprint, lowering energy costs, and improving energy self-sufficiency by putting a residential Solar Photovoltaic (PV) system on his own home in Cambridge. Installed by S+H's Renewable Energy Division, this medium-sized 3.7 kilowatt PV system produces approximately 65% of the electrical needs of the home. It uses 22 175-watt SunTech solar panels and a Unirac racking system tied into the house electrical panel through an Xantrex inverter to produce utility-grade electricity. Any electricity not used by the home is sent back into the electrical grid and sold to NStar.