Jim Bermingham had moved about 20 times in his life as a foreign service officer and consultant when he and his wife, Sue, finally settled into a spacious Northwest Washington townhouse. It had room for all the treasures and trinkets they had accumulated over the years.

Less than three years later, in March 2004, Bermingham suffered a stroke. Suddenly, the staircases linking the house's four stories were daunting.

But the couple wanted to stay put. Their home in the gated Hillandale community was supposed to be "the last stop."

Their solution was one that is becoming increasingly popular: They added an elevator to the house.

"Moving, selling the house, getting a good price -- that is too much commotion, you know?" said Bermingham, 66.

The Berminghams and others committed to living in a multilevel house or a familiar neighborhood are finding that a home elevator can be the key to remaining as they age or face infirmities that make stairs challenging or unthinkable.

Elevator manufacturers and contractors say installation of residential elevators has increased explosively in the past five years as aging baby boomers plan for the rest of their lives. More new construction features home elevators, too, either built-in or as an upgrade option.

"I used to talk to 10 people a year -- now I talk to 10 people a month about installing elevators, probably more than that," said Buck Robinson, who heads up the home elevator and stairlift division for Delta Electrical in Upper Marlboro.

"The market has grown by double-digit percentage rates for the past few years and we expect that to continue," said Silvio Albino, a spokesman for Otis Elevator Co., the world's largest manufacturer of elevators. The company says 12,000 new residential units are sold each year in North America.

The Washington region is "one of the largest growth areas we have right now," said Ray Varner, East Coast sales representative for Inclinator Co. of America, which bills itself as the oldest residential elevator manufacturer in America, dating from 1929. It can cost tens of thousands of dollars to add an elevator to a house. Still, Varner said, "prices of homes now on the East Coast have gravitated to the point where the elevator is not changing the cost of your mortgage to a great degree."

"Obviously, retrofitting has been a huge part of our business. People want to age in place. People don't want to give up the neighborhood they love, the friends, the school, the shopping. . . . They can change their home to meet their needs," said Jim Quinley, general manager for the residential elevator division of ThyssenKrupp Access, another elevator manufacturer.

And they do change their homes.

Townhouses in upscale Hillandale can be retrofitted with an elevator by knocking out a stack of closets, and the Berminghams' neighbors have also installed elevators. The ride is smooth and quiet in newer elevators and the elevator entry looks like a closet door with call buttons. The only problem, Sue Bermingham said, is that the elevator cab in her house -- at 21/2 feet square -- cannot accommodate a wheelchair. The design of the house didn't allow a larger elevator, she said. "Fortunately, my husband learned to walk enough so he could walk into [the cab] and we had a seat made," she said.

Elevator professionals say that a good-sized cab for a wheelchair is at least three feet by four feet.

"Often, more important than the space of the elevator is the traffic pattern from floor to floor getting into the elevator," said Jerry Hergenrader, vice president of technical marketing for Ashley Corp., a Richmond-based accessibility dealer.

Three-foot by four-foot cabs work well for wheelchairs if the hall doors going into the elevator share perspective or direction on every floor, Hergenrader said. Otherwise, a wheelchair user must negotiate a "parallel park maneuver'' to exit.

The elevator in Lynn Anderholm's Alexandria house, at 40 inches by 54 inches, can accommodate not only her wheelchair but also an attendant. Anderholm, in her early fifties, suffers from Parkinson's disease. She installed the elevator as part of a project to rework the entire house so she could move about.

But, she extended the reach -- and cost -- of her elevator for another reason. People ask her why the elevator goes to the third floor -- her bedroom is on the second.

Well, Anderholm wants to be able to "kiss my grandchildren good night" -- when she does eventually have them -- in the guest bedrooms above. The elevator is "giving us the ability to stay in our home, and to stay graciously in our home," she said.

Her family has lived in their neighborhood for 22 years and simply didn't want to leave. "Our neighbors are our family, our support system," Anderholm said. Besides, nearby there are "four Chinese restaurants, two grocery stores, two movie rentals, drycleaners. . . . Everything is right here."

Real estate agent Phyllis Jane Young said she tries to convince buyers to consider adding an elevator if stairs may be an obstacle.

People "shouldn't be forced to leave because of bad knees," said Young, associate broker with Coldwell Banker-Pardoe Real Estate on Capitol Hill, where most homes are multiple stories.

Take Joan Joshi, 73. She is fit as a fiddle now. But she figures that may not always be the case.

The part-time consultant for international organizations likes city living, so she quit the Maryland suburbs in 2003 for a house on Capitol Hill, within walking distance of Metro and close to downtown. For her, it's in a beloved neighborhood where she once lived with her late husband. She snapped up a townhouse that had been previously retrofitted with an elevator.

It will allow her to remain independent as she ages, she said.

"Chances are I won't leave here until I can't live by myself anymore," Joshi said. "I like the neighborhood, the privacy, to live alone. My mother lived in one of those retirement homes and I hated it. It is not for me. The elevator will stave it off."

Builders also are fashioning homes with elevators for added convenience and the luxury touch, as well as for the anticipated flock of retiring baby boomers.

For example, PN Hoffman built a few townhouses with elevators with maple cabs and glass panel doors in its Tenley Hill development in Northwest Washington four years ago. In a new Eakin/Youngentob development, the Brownstones at Park Potomac in Potomac, many townhouses boast elevators as an option or a standard feature.

You "can bring up hors d'oeuvres to the rooftop terrace on the third level relatively conveniently," said Mark Stahl of PN Hoffman. "You can entertain conveniently."

Whether or not family members have physical limitations, many homeowners gush about how their home elevators double as dumbwaiters, carrying laundry, groceries, vacuum cleaner, Christmas decorations, sofas, luggage -- even the grandkids' strollers.

Costs for a home elevator can run anywhere from $12,000 to $30,000 for the machinery alone. However, construction can run up the bill, especially if a renovation is required to build a hoistway, the shaft in the building through which the elevator travels.

When Bill Scott's wife, Joan, was diagnosed with Lou Gehrig's disease, they thought they would have to move or Joan would have to live in the basement of their Davidsonville house. They considered a condominium, but it offered less space. Like many in the region, the Scotts have "lived all over the world" and wanted to settle down. Besides, their children and grandchildren had gotten used to coming to the house.

So, the couple spent $21,000 on a three-floor elevator with a three- by five-foot marbled-floor cab. The hoistway cost $45,000 to build. Although elevators themselves can be installed within two weeks, a good amount of time will be spent on the renovations or construction.

But for many, it is worth it. "Within three months, we had the elevator running and it has allowed us to stay here," said Bill Scott of their neighborhood, which is 15 minutes from downtown Annapolis but also rural enough to be near a dairy farm.

The Berminghams' elevator took about eight weeks to install and cost $38,000, total. The four-level elevator was $26,000; the balance was spent preparing a well of closets to become the hoistway.

The townhouse was designed in anticipation of a retrofit, so the construction cost was less than reconfiguring a more awkward space to build a hoistway and machine room.

"A lot of those where we put additions on the back of the home [entail ] a bump-out," said Robinson of Delta Electrical "That is pretty popular because it doesn't chop out from the existing floor plan."

Count on the construction costs being equal to the cost of the elevator, said Tim Blair of Premier Lifts Inc., a Timonium, Md.-based dealer.

Of course, some splurge by jazzing up their home elevators, with wallpaper or even more elaborate decorator touches. "One customer had all jade floors," Ashley Corp.'s Hergenrader said. There is "nothing saying these have to be dark doghouses, dark silos. . . . You can really make them cool," he said.

Indeed, Anderholm is considering hiring a painter to create a garden-themed mural inside her elevator.

Jim and Sue Bermingham installed an elevator in their four-floor Northwest Washington town home after he suffered a stroke. Limited in size by the closets the shaft replaced, Jim Bermingham's Hillandale townhouse elevator cannot accommodate a wheelchair but does have a seat.