4,707: Kilowatt hours of energy provided by photovoltaics on the roof of William and Deborah Lord’s house in Kennebunkport in 2007

16: Number of photovoltaic panels on the roof

2,900: Square footage of the house

$8: The Lords’ approximate monthly electric bill (standard hookup charge)

$4.88: Price, per volt, of installing photovoltaics

Source: solarhouse.com