For Arthur Bennett, blackouts now come with a soundtrack.

When last month's "thundersnow" knocked out power in Bennett's Montgomery County neighborhood, the preindustrial hush inside his house - when even the refrigerator seemed to hold its breath - soon gave way to the two-stroke roar of engines up and down his block.

"As soon as the power goes out, the generators come on," said Bennett, a resident of the tree-filled, outage-prone village of Garrett Park. "In the last couple of years, it's gotten to be like a bunch of lawn mowers running all night. It means I don't sleep very well."

Bennett, like many residents of Pepco's service area in Maryland and the District, has concluded that blackouts are likely to get even louder as the utility's fed-up customers increasingly turn to backup power. According to retailers and electricians, home generator sales are booming in the area Pepco serves, especially since the company has been plagued by repeated, prolonged outages over the past few years. Portable generators sold out at several home stores after the latest storm, and installers report that sales of high-end whole-house units have skyrocketed.

Jim Holt of Gaithersburg's Holt Electrical said his sales of home generators have been climbing steadily and reached a near "level of panic" after the last blackout - mainly on Pepco's turf.

"We've got people begging us to come out right now, offering to pay extra," Holt said. "A few years ago, we had a lot of sales in McLean and Great Falls, places where they have a lot of trees. Now it's all Potomac, Bethesda, Silver Spring. That's Pepco."

Amanda Keller, office manager of Baltimore-based Innovative Energy Systems, which operates in areas covered by both Pepco and Baltimore Gas and Electric, said, "It's definitely been good for business.

"Our biggest activity these days is not up here, it's down in the D.C. metro area."

A Pepco spokesman said the utility was aware of the trend.

"We know some people are buying generators, but don't give up on Pepco," said Bob Hainey, the utility's manager of media relations. "We want to provide safe and reliable electricity for all of our customers, and that's what we're working on."

A social network

But as generators pop up in more back yards, so do questions of generator etiquette. How many lights is it polite to have on when the rest of the block is dark? (One Garrett Park family raised eyebrows during the January outage by firing up their still-hanging Christmas lights). How many cellphones and iPods is it acceptable to take over to a neighbor's generator-equipped house for a quick charge? How late is too late to run the equivalent of a minibike engine right outside your neighbor's window?

The noise "has definitely become more of an issue," said Stan Edwards, chief of Montgomery's Environmental Policy and Compliance Division. His agency responded to 15 complaints of generator noise last year, up from an average of one or two in past years.

Montgomery law caps household generator noise at 65 decibels (a level similar to a vacuum cleaner) in the daytime and 55 decibels (about the same as a window air-conditioning unit) after 9 p.m. Most commercially available generators far exceed those levels, Edwards said, but the racket can be muted by careful placement and noise-dampening fences.

Most of the complaints are negotiated away, he said.

"We may ask them to turn it off by a certain hour or to move it," Edwards said. "Sometimes we find no violation at all. When you're sitting on your deck at night, it may seem awfully loud, but it may not violate the ordinance."

Edwards said tensions run highest in summer, when a power loss means air conditioners are down, tempers are high and windows are open.

Amy Cassagnol, a Silver Spring teacher, said she resorted to guerrilla tactics in August when a thunderstorm cut power to her block and she found herself sandwiched between two neighbors' backup generators. In the small of the night, she called one of the offending houses and held the phone out the window.

"Do you hear that?" Cassagnol yelled. "I can't sleep because of your generator. Please turn it off."

"No way," the neighbor said. "It's running our air conditioner."

All-day drone

After that same storm, Mary Jane Ruhl called police to report what sounded like a "jet engine" running in the yard behind her Alexandria home. Ruhl, a chemist at the U.S. Patent Office, said she was recovering from surgery, sweltering in the heat and slowly going nuts from the all-day drone coming from beyond her garden. But the officer who responded said he couldn't do anything as long as the machine was off by 11 p.m., per city code.

"After four days, I was shaking and my teeth were chattering," said Ruhl, who lost power again last month. "Now after this last one, everybody on the Listserv is talking about getting a generator."

Ron Jolles said he gets few complaints about the noise of his generator in Northwest Washington, in part because he is quick to hook up his neighbors. When the power dies, Jolles cranks up his 6.2-kilowatt gas-powered unit, runs extension cords to as many as five surrounding houses and becomes a micro-grid in his part of the Barnaby Woods neighborhood. He also serves as neighborhood charging station and packs his freezer with neighbors' food.

"I was certainly aware of the noise issue with an internal combustion engine," said Jolles, a former contractor and construction lawyer. "I conquered that by offering cords. But I would have offered them anyway. You live in a community, you share."

Susan St. Maxens of the Chevy Chase section of the District is another practitioner of extension cord diplomacy. She and her husband, Tom, bought a backup generator when they began to worry that the frequent outages would hamper their home-based consulting business.

"It's pretty bad," St. Maxens said of the pit-stop racket that emerges from her yard every time a transformer blows. "You can hear it a block away. We feel terrible."

The couple have made a noisy peace with their neighbors by offering outlet space to the two nearest houses. On powerless summer nights, they voluntarily turn their generator off and sweat through the wee hours with everybody else.

"I know there are people who are pretty snarly about it, but no one has said anything to us firsthand," St. Maxens said.

One thing both generator owners and their juiceless neighbors can agree on is the frustration of having to debate this issue at all.

"I really think it's kind of scandalous that in the capital of the world, we've got third-world reliability for electric power," said Larry Posner of Shepherd Park in Northwest.

Posner and several neighbors have set up a meeting with a vendor Wednesday to explore a possible generator consortium. It is unexpectedly familiar work to Posner, who spent his career as a consultant to developing countries.