“The noisiest it gets is 35 decibels,” roughly the sound of a quiet conversation, he said of the whir of the blades. The turbine, which looks like a large wagon wheel, has a ring around its blades designed to diffuse noise and limit vibration. “The air is steered toward the diffuser ring and dispersed, rather than leaving the blades with a ripping noise,” Dr. Anderson said.

The turbine costs $10,000 to $12,000 including installation, said Michael Ford, manager of the renewable energy business unit at Cascade Engineering. When the wind is blowing briskly at 30 miles an hour or more, it will generate 1.5 kilowatts of electrical power, he said. Enough, for instance, to run fifteen 100-watt light bulbs.

“You need a strong average wind speed,” he said, recommending that prospective customers make careful measurements before they buy. “Don’t trust your memories about the wind power around your house,” he said. “People always remember when it’s windy,” but forget about the lulls.