The installed photovoltaic system consists of (42) 230 watt Sunpower panels, designed with a black backsheet to blend in with the roof. The system was designed to fit exactly on the southwest dormer which faces 220 degrees (North is 0 ˚ and South is 180˚) and is completely unshaded. Shading can have deleterious effect on solar production. Sunpower panels have the highest efficiency of any panel available today at 20% and are warrantied for 25 years, which is longer than many roofs.
Despite common misconceptions, the Cape is a great place to consider solar. With great incentives available from the MA Clean Energy Center as well as federal tax incentives, PV is a great investment. The array on the house is estimated to produce approximately 11,800 kWh annually with the highest month being July (1320 kWh) and lowest December (530 kWh). The mechanicals at the house are all electric to match the production on the roof. We will heat and cool with minisplit heat pumps by Fujitsu and use electric heat pump hot water heaters for domestic hot water heating. Any excess production (say in January when no one is at the house) will be applied towards the electric account and used in months with higher occupancy. Net metering also allows excess production to be credited to other NStar accounts locally.
Estimated production: 11,800 kWh
Estimated loads (assuming full time occupancy)
Heating: 8,000 kWh
Cooling: 2,000 kWh
DHW: 1,400 kWh
Lighting & Appliances: 5,500 kWh
Total: 16,900 kWh
Solar Installer – E2 Solar, Inc
For more information about this project and A3Architects, INC – please visit: www.a3architectsinc.com