When Linda Mclean's husband, Michael, turned 50 last year, she wanted to buy him something really special.

So she did: a hot tub and entertainment center where he can lie under the stars, being massaged by warm bubbles while flicking through television channels, listening to surround-sound stereo, or watching a DVD on a pop-up plasma screen built into the spa.

"Our back yard is a resort for us," said Mclean, who lives on a two-acre lot in Brookeville in upper Montgomery County. It includes a swimming pool and a red cedar gazebo that houses the hot tub. "It's our palace."

And the Mcleans aren't the only ones who feel that way. Homeowners across the country, whether they're sitting on acres of land or facing onto a postage-stamp-sized patio, are expanding the livable square footage of their homes by heading out their sliding doors and creating new living spaces outside.

According to the Census Bureau, Americans spent $17.43 billion remodeling outdoor spaces in 2003, 42 percent more than in 1998. And they said they planned to spend $3.2 billion furnishing them, according to a 2003 survey by Casual Living magazine.

Sandy Clinton of Clinton & Associates Landscape Architects in Hyattsville said that what homeowners are looking for outside is "an extension of their indoor space. They're trying to create a room outside. Sometimes it's a kitchen, sometimes it's a living room, sometimes it's a dining room. Oftentimes, it's all three."

To outfit their outdoor rooms, American homeowners are buying anything from a $100 free-standing fireplace, called a chimenea, to a $30,000 outdoor kitchen fitted with an under-counter refrigerator, warming drawers, a trash compactor and cold beer on tap. And manufacturers are fueling the demand with an array of new products.

"There's been a dramatic change in the product mix for outdoors in the past five years because of the boom in outdoor living," said Cinde W. Ingram, managing editor of Casual Living magazine. "There's all kinds of new products now, new fabrics, new colors. You can tell the difference in the stores."

And outdoor living isn't a luxury reserved just for the rich.

"It can be low-budget, or it can be the 'sky is the limit,' " said Leslie Wheeler, director of communications for the Arlington-based Hearth, Patio and Barbecue Association. "Here in the Washington area, it's that, and everything in between."

Wheeler said shipments of free-standing wood fireplaces went up 96.2 percent from 2002 to 2003. Shipments of gas products, such as grills, fueled either by propane or natural gas, went up 44.5 percent over the same period.

"More and more people want outside features for their homes," said Gopal Ahluwalia, director of research for the National Association of Home Builders. "It's the same mentality that makes people move to Florida -- a love of the outdoors."

Ahluwalia said studies show that the desire for more outdoor features crosses all ethnic lines and income levels. "Everybody wants them," he said.

Ahluwalia said that in the upscale market, 8 percent of new homes now come with an outdoor kitchen, compared with half that 20 years ago. Half of all new single-family houses built last year had porches, up from 42 percent 10 years ago. And 45 percent of new homes built in 2003 had a patio, compared with 37 percent in 1993.

Local builders say they almost always rough-in a gas line for outside cooking these days when they build a house, even though most of their clients finish their outside spaces later.

"A gas line outside used to be more of an option," said Phil Leibovitz, principal at custom builders Sandy Spring Builders in Bethesda. "Now it's pretty much standard for us. We didn't used to do that three or four years ago. People are asking for screened-in porches a lot more, too."

At the most extreme end of the outdoor living trend is a product such as the U9000, an outdoor kitchen-entertainment center made by Cal Spas of Pomona, Calif., that retails for $30,000. The outdoor kitchen includes a gas grill, separate burners, a refrigerator, a sink, a fire pit, a fireplace, a seating area and an entertainment center with a 42-inch plasma TV screen that rises from the countertop.

"We built it mostly to show off what we could do," said Casey Loyd, president and chief executive of Cal Spas. "We didn't think we'd sell a lot of them. But it's turning out to be one of our hottest items." Loyd said Cal Spas has sold some 2,000 U9000s around the country since the product was launched in April.

But even for just grilling burgers on a hot summer night, gone are the days of the humble hibachi sitting by itself outside the kitchen door. Americans spent $3 billion on barbecues and accessories in 2003, according to the Hearth, Patio and Barbecue Association; a recent poll by The Washington Post found that 46 percent of area residents, when asked about their weekend, said that they had barbecued food outdoors.

"Grills are larger and fancier than ever before," said Bob Garner, director of design at Reico Kitchen & Bath, which has nine appliance showrooms in the Washington area. "The amount of heat they generate is almost commercial grade. Some have halogen lights incorporated into the top so you can see in the dark. Others have side burners, warming drawers, rotisseries. Some offer heaters incorporated on the side or underneath so that you can stay warm. Consumers want outdoor appliances to do the same things that their appliances inside do."

Around those new outdoor appliances, consumers are then creating distinctive outdoor spaces.

"We're getting requests for more and more elaborately constructed spaces further from the house," said Lila Fendrick of Lila Fendrick Landscape Architecture and Garden Design in Chevy Chase. "Like garden pavilions with remote kitchens, living rooms and dining rooms."

Paul Albright, president of East Coast Wholesale Distributors Inc. in Gaithersburg, said more local consumers are buying gazebos and then using them to create "outdoor environments" around their spas, grills or picnic tables.

He said his company, which sells hot tubs, decks and other outdoor amenities, has had a 250 percent increase in sales in the last five years. "It's amazing how much stuff people are putting into their back yards."

But a pleasing outdoor space can also be created without spending thousands of dollars on fancy new products, "in the tiniest of spaces and with the tiniest of wallets," landscape architect Clinton said. "A room outside can be as a simple as a small Georgetown garden with two chaise longues, an end table, and a beautiful bowl that captures rainwater and acts as a reflective surface. It's all about scale and proportion."

Fabrics for outdoor furniture are also now much more varied -- and durable -- than they were just a few years ago.

"There are performance fabrics that have been developed in the past three or four years that can withstand the most punishing elements outside," Casual Living magazine's Ingram said. "And they look just as good and have the feel of interior fabrics." Ingram said manufacturers have moved away from green or sand colors for outside, too, and are now offering spa blues, hot pinks, oranges and reds.

She said sales of outdoor rugs have taken off in the past couple of years. And outdoor fixtures such as lamps and sconces are now similar in design to what's available for inside the home, but made to withstand the elements.

This interest in creating rooms outdoors, however, comes at the same time that single-family lots are shrinking rather than growing. And it's not as if the great outdoors is a new invention, either. So what's fueling this fascination now?

Outdoor spending is part of the overall boom in home remodeling spending, which has been fed by low interest rates and the steep run-up in real estate values. Americans have tapped the ever-increasing equity in their homes to upgrade their properties, both inside and out.

Manufacturers and retailers say the Sept. 11, 2001, terrorist attacks also boosted sales of outdoor home products such as hot tubs and gazebos. "It has a lot to do with 9/11," Cal Spas' Loyd said. "People were terrified to travel and not that comfortable overseas. So instead of spending money on lavish vacations, they started spending it on their homes."

American homeowners may also be striving to duplicate some of the lush outside spaces they have encountered at hotels, resorts or elsewhere in their travels.

"We're creating our own lives inspired by images from films and visits to places like Napa Valley, Tuscany and Provence," said Elvin McDonald, deputy editor for garden and outdoor living at Better Homes and Gardens magazine. "The image of a big dining table outdoors under linden trees looking out over vineyards is irresistible. Everyone wants that kind of experience."

Landscape architect Clinton said that the desire to create a pleasing outside space has become "totally mainstream." She admits, however, that outside projects can easily run into the hundreds of thousands of dollars. Her own firm, for example, doesn't take any project for less than $100,000; the most expensive landscaping project she's done in the area was a $4.5 million revamping of a 20-acre horse farm, which included a new swimming pool, spa, pool house, tennis court and pond.

In resale terms, is it worth it to spend all that money on the exterior of the house? For Seth Perretta and David Leary, that was an important factor when they recently re-vamped their yard in the Tenleytown neighborhood of the District.

Out of one 160-yard-long lawn, Perretta and Leary created a "three-room design." The first "room" includes a slate terrace bordered by plants; it acts as an outdoor dining room. The second "room" is a lawn area surrounded by beds of perennials; it's for kicking a ball around with their 3-year-old. The third "room" is the pool room, where they built a rectangular dark-bottom pool surrounded by a stone wall that follows the outline of the pool.

"We were absolutely thinking about resale," Perretta said. "Our thoughts were that the yard in its current state wasn't good for resale, that as a big swath of green grass, it was just an untapped asset."

Just one year after they finished their extensive -- and expensive -- landscaping project, they sold their house.

"Did we get every dollar back that we spent on our yard?" Perretta said. "It's hard to say. It certainly maximized what we got, because we got an obscene amount of money for our house."

But not everyone seems to care all that much. "Getting the money back at resale is not the first question out of people's mouths when they do these projects," said Richard Arentz of Arentz Landscape Architects LLC in the District. "It's much more about the quality of their lives now."

He said homeowners are spending more and more time in their outdoor environments and more and more money creating them. "I've seen people spend $60,000 for one tree," he said.

Linda Mclean created an outdoor living area that includes a pool, patio and gazebo-enclosed spa with an entertainment system.A red-cedar gazebo houses a hot tub and entertainment center, with a pop-up plasma TV screen and a surround-sound stereo.A chimenea, a free- standing fireplace.The Cal Spas U9000 is an outdoor kitchen-entertainment center that includes a grill, side burners, refrigerator, fire pit, fireplace, a seating area and an entertainment center with a 42-inch pop-up plasma TV set. The company has sold 2,000 of the $30,000 units since it launched the product in April. The back yard at Linda and Michael Mclean's house includes a pool with a waterfall flanked by a patio. "Our back yard is a resort for us," Linda Mclean says.