by Matthew Brady

Before finding an expert contractor, Angie's List member Elisabeth Tien of Sudbury, Mass., hardly needed an alarm clock in the winter. The steam heat in her 1790 home did the job about 3 or 4 o'clock most mornings.

"The heat would hit the cold pipes and it would do that cracking sound," she says. "A lot of people think that's normal, but it was really loud."

The systems - common throughout Boston and the Northeast - involve a boiler in the basement that forces steam up into radiators in each room.

Builders stopped installing them in the 1940s, says Charlie Lovett, owner of highly rated Lovett Plumbing & Heating of Arlington, Mass. "It's considered prehistoric and it's very inefficient," he says. But the systems are found in many older homes, so Lovett taught himself how to repair them.

Massachusetts doesn't require a contractor to have a hydronics license to work on home steam heat, but a licensed plumber or HVAC specialist is often needed to repair them.

Tien says she called four or five plumbers before hiring highly rated Trethewey Brothers Inc. in Boston. "Everybody had a different story about how to fix it," she says. "He knew what he was doing and it was done. No more sound." The repair required pitching a pipe at the right angle to allow the steam and condensation to move through the system.

Noise is the No. 1 complaint, contractors say, but they add that a properly set-up system should be virtually silent. "Many of them have been altered in ways that make it very difficult to keep them working the way they should have been working," says Dennis Foley of highly rated Dennis Foley Plumbing in Somerville, Mass. The main advantage to steam heat, he says, is that it is often cheaper to keep it running than to replace it with a modern system that could cost $20,000 or more.

Lovett also says that compared with a forced-air system, a radiant system such as steam can help allergy sufferers because air is not stirring up dust.

Steam heat isn't cheap, however. Tien says during the coldest part of the winter, she spends between $500 and $700 every three weeks on oil for her boiler. "It's pretty tough in the winter," she says. "It's not economical."

The pressure setting on a steam boiler is something homeowners should pay attention to, says Dan Holohan, a contributor to Old House Journal and founder of heatinghelp.com. "It's all about venting. The air has to get out before the steam can travel," he says. "Often when they can't get the air out of the system, they'll just automatically crank up the pressure, which kills the fuel bill. The Empire State Building runs on about a pound and a half of pressure, and yet a knucklehead will crank the pressure in somebody's house up to 5 or 6 pounds. Houses are meant to run literally on ounces of pressure.