Daniel Lahr cherishes his 1,400-bottle wine collection, an eclectic mix of French Bordeaux and Burgundy, northern and southern Rhone and California cabernets. But, he admits, he hasn’t been treating it as well as he could, storing it in a cold, dark corner of his basement.”It’s actually not a bad environment, but it’s not ideal,” he said.

“I spent a lot of money for the wine, and I enjoy aged wine. A lot of stuff I bought I can’t drink for eight or 10 years.”

So he commissioned Classic Cellar Design, of Washington, D.C., to build a 2,600-bottle wine cellar in the basement of his Rockville, Md., home.

When it is completed, it will have limestone floors, mahogany racks, wrought-iron doors, double-insulated windows and a vineyard mosaic.

“We started out thinking we would just build a closet,” said Dr. Lahr, a 45-year-old orthopedic surgeon.

“We figured we would get the basement done and got carried away with it.”

The wine cellar has become a must-have amenity for high-end homes, much like the home theater and the gym had been. A growing number of new-home developers are offering wine cellars as an option.

Gopal Ahluwalia, staff vice president of research for the National Association of Home Builders, said that “in the next few years, you will be seeing wine cellars as a standard feature in upscale homes,” which he defined as being 4,000 square feet or larger.

He said much of the demand comes from baby boomers who have collected wine over the years. But younger people who can afford expensive homes want all the upscale features they can get, he said.

Not even the shaky economy and the uncertainty of the housing market have kept owners of upscale homes from building wine cellars.

In fact, some believe it will increase the value of their home.

“I think it’s become a selling feature for new homes and existing homes,” said Josh Farrell, a product specialist and wine director of Wine Enthusiast magazine.

“If you’re reselling your home and it has the swimming pool and it has the wine cellar, obviously that is going to add to the price.”

Builders say wine cellars are an extension of the idea that the home is not only a place to live, but also a place to entertain.

Much of that entertaining is done in the home’s lower level. It used to be that homeowners wouldn’t even finish their basements; now the space contains movie rooms, bars, pool tables and other adult playthings.

An average cellar holds about 1,000 bottles, but some can hold thousands more.

Prices, too, vary wildly, from the $10,000s to $100,000 and higher, according to several cellar designers.

One reason that wine cellars have become popular is that as more people drink fine wines, they are learning the value of letting some of them, particularly tannic reds, improve with age.

For many people, a home wine cellar is also about building and protecting a valuable investment.

If you want your wine to last a long time, here’s what the experts recommend: good ventilation and a stable temperature, about 55 degrees; humidity of 50 to 60 percent, though other wine-cellar experts say 75 percent works; a vapor barrier; and proper insulation.

For your shelves and racks, you probably want redwood or pine, though mahogany is also aesthetically pleasing.

The goal is to avoid rotting, mold and the drying out of the cork.

“Over the last couple of years, the technology for the wine cellars has really been improved,” said Steve Goldstein, founder and a co-owner of Classic Cellar Design.

“People feel more comfortable” building them, he said.

Builders of upscale homes started making wine cellars bigger and more ornate. Several designers said they can include tasting rooms, cigar-smoking areas, bookshelves, fur rooms, commissioned art and more.

Some people have found ways to build wine cellars themselves.

Gray Mosby, president of the wine distribution company Brightberry Imports, chronicled his building of a 660-bottle wine cellar in his Arlington, Va., townhouse in a show on the Do It Yourself Network.

Though the network paid for much of his project, he said, a 50-case, 600-bottle cellar can be built for less than $2,500.

Storing wine can be done on an even tighter budget. Small wine refrigerators have become more affordable, said Mr. Farrell, of Wine Enthusiast. An apartment dweller can fit one in a kitchen.

“That’s become a very big business,” he said.

“It used to be if you wanted something like that in your home, you’d have to spend $1,000 or more.

“Now they come in all sizes, from six bottles to 25 bottles. They sell so well that it makes sense to carry them in all sizes.”

And if you think a wine cellar can only be in a basement, you’re wrong.

Vintage Wine Rooms, for example, has proposed building wine lockers in the clubhouse of a condominium community in Virginia, said owner Joe Duffus. Other cellar designers said they have built cellars or storage rooms inside condo units.

Lorne Greene, 37, and his wife, Emily, opted for a smaller storage area on the main level of their Bethesda, Md., home.

Tired of going out and buying whatever wine they needed for an evening of entertaining, they decided they wanted longer-term storage.

So they built one for about 250 bottles in an area between the dining room and the family room; a glass door will make it visible from both rooms.

“For us, what makes sense is something more moderate-size on the main level, someplace to store wine properly and get to easily,” Mr. Greene said.