On a recent sunny afternoon Bob Loebelenz pauses to gaze 72 feet into the air at the spinning blades of his wind turbine, a small "clean, free electricity" smile creasing the corners of his mouth.

While giant wind turbines that supply power to utilities sprout along ridgelines across the United States, far smaller residential wind generators, like the one Mr. Loebelenz erected in 2003 to power his suburban Boston home, are still unusual in densely populated places.

That may be changing. Across the country signs are growing that "small wind" (a category that includes wind generators geared to supply a single home) is catching on in suburban and even urban settings.

"My phone has been ringing off the hook," says Mark Durrenberger, president and founder of New England Breeze, a Hudson, Mass., wind and solar power installer.

Improved generator technology, more financial incentives, rising electric rates, and energy-security concerns have opened the way for small-wind power to bloom in unlikely places.

"Small wind really seems to be taking off for residential, small business, and farm use," says Trudy Forsyth, leader of the distributed wind program at the National Renewable Energy Laboratory in Golden, Colo.

The installed capacity of "on grid" small-wind residential generators has almost tripled, from 1,300 kilowatts nationwide in 2006 to 3,000 kilowatts last year, says the American Wind En­­­ergy Association (AWEA), a Washington-based trade organization. The number of residential installations rose from 400 to 1,200 units in the same period.

Supplying that tiny but red-hot market are dozens of new companies that have popped up since 2000. Though a half-dozen companies dominate the market, AWEA tracks about 45 US manufacturers. With demand strong overseas, too, the US is the world leader in small-wind power, exporting more than half of what it sells.

"The growth we're now seeing in small-wind residential in the US is impressive," says Ron Stimmel, who tracks the small-wind market for AWEA. "Advanced technology and electronics have made these units more reliable, and more states are now offering incentives to build them."

At least 26 states have tax or productivity incentives or other subsidies to support wind energy, Ms. Forsyth says. But strong growth is happening even without the federal tax incentives enjoyed by solar panels and big utility-scale wind turbines, she notes.

Countervailing breezes are blowing.

Long held down by high up-front costs, lack of federal subsidies, and neighborhood opposition on aesthetic and noise grounds, small residential wind-power use continues to grow far more slowly than solar photovoltaic "panels," experts say. Some also oppose small-wind units claiming they are "bird Cuisinarts," Loebelenz says, though he has never found dead birds by his unit.

Another major hurdle is zoning laws. While few states or the 25,000 local zoning authorities have laws specific to wind power, that's changing, Mr. Stimmel says. Five states – Wisconsin, California, Michigan, Vermont, and New York – now prohibit local zoning laws from blanket small-wind prohibitions.

"Zoning is always an issue, it's something we understand now and we go in prepared to show the benefits," says Don Mosher, president of Southern New England Wind Power, based in Portsmouth, R.I.

Even so, zoning battles over wind power are increasing. Loebelenz had to hire a lawyer. Even then, he might have lost the fight had not an octogenarian neighbor, Beverly Ryburn, not come to his rescue by rallying others to help.

Pointing to a plaque on his tower that reads: "The Beverly," Loebelenz notes: "I named my wind generator after her because, without her, it probably would not have been built."

Wind power can be expensive. Small wind turbines for homes run in the 2- to 10-kilowatt range. A smaller machine can cost from $12,000 to $60,000, installed. A rule of thumb: Turbine systems cost about $6 to $8 per watt (1 kilowatt = 1,000 watts), installed.

Loebelenz also has a big solar array on his barn roof next to the wind turbine. On many days, when the wind generator is humming and solar panels are cooking, he's generating far more energy than he uses, so he sells the overage to the power company.

It's that link to the power grid that's been key to small-wind growth. While wind power has long been popular for "off the grid" homes miles from power lines, growth in residential "grid tied" homes lagged until "net metering" laws were passed. Net metering means a utility must buy back extra power.

Better wind technology has helped, too. Lighter magnets in the generators, blades that adjust to wind conditions, and units that wirelessly report how much power they're making – along with global-warming concerns – are creating a "perfect storm" of interest in suburban, even urban residential wind power.

"Everything we had done historically was off-grid and international, but ... about six, seven years ago really, things started percolating," says Andy Kruse, vice president of Southwest Windpower, the nation's largest small-wind manufacturer, in Flagstaff, Ariz.

The company's newest small turbine – the 1.8-kilowatt "Skystream" – is aimed at the residential market. In February, the company said a Skystream would be erected at the Maine home of former President George H.W. Bush.

But Robin Wilson already has a Skystream wind generator atop a 45-foot pole sticking out of her new zero-energy home in San Francisco's Mission District. Hers may be the first such "urban residential turbine," though she can't be quite sure.

Ms. Wilson may have started something because San Francisco Mayor Gavin Newsom visited her home recently and says he's forming a group to study the idea of expanding residential wind throughout the city.

"I love the idea of being a zero-energy home and wind is helping me get there," says Wilson, whose neighbors "just love it" she says. The "scimitar-style" high-tech blades emit little noise, she says, "just a little hum."