Cascade Engineering. The rooftop-mountable Swift turbine is designed for urban and suburban homes, starting up in 8-mph winds. It can produce 1,900 kWh per year at a 13.4-mph average wind speed, says the firm, and is never louder than 35 decibels, equivalent to a whisper. The turbine measures 7 feet in diameter. 866.544.5520. www.swiftwindturbine.com.
Cascade Engineering. The rooftop-mountable Swift turbine is designed for urban and suburban homes, starting up in 8-mph winds. It can produce 1,900 kWh per year at a 13.4-mph average wind speed, says the firm, and is never louder than 35 decibels, equivalent to a whisper. The turbine measures 7 feet in diameter. 866.544.5520. www.swiftwindturbine.com.

Cascade Engineering.

The rooftop-mountable Swift turbine is designed for urban and suburban homes, starting up in 8-mph winds. It can produce 1,900 kWh per year at a 13.4-mph average wind speed, says the firm, and is never louder than 35 decibels, equivalent to a whisper. The turbine measures 7 feet in diameter. 866.544.5520. www.swiftwindturbine.com.