NASHVILLE, Tenn. — Missy Phillips knew she had a big problem on her hands when her boyfriend's 18-year-old son ransacked their house looking for the stash of unwrapped Christmas presents.

To keep the nosy teenager from finding the stereo, video games and hunting bow she and her boyfriend bought him, Phillips had to go out of the house — and into a self-storage unit — to hide the gifts until Christmas Eve.

Around the holidays, the units typically used to store furniture and household items are becoming temporary outposts for adults to hide and wrap gifts for kids and big-ticket items like televisions or bicycles for spouses. In Nashville, one storage service bills their smaller units as "Santa Closets."

"It's a great concept because it takes away that worry that they're going to find them," said Phillips, who lives in the St. Louis suburb of Alton, Ill. "Therefore, you have the element of surprise on Christmas."

Jane Davies, who manages Abbott Self-Storage in Nashville, said several wives this year have rented the facility's "Santa Closets" to house large presents like big-screen TVs and recliners for their husbands.

Absolute Storage Management in Memphis, which operates Abbott and other storage facilities in the Southeast, offers 4-by-4-foot units from early November through Christmas for a $1 a day.

"It's a little hard to hide a big-screen TV, recliners, bicycles," Davies said. "A lot of houses, condos and apartments don't have the storage space.

"It becomes a convenience because if you do have snoopy kids — like I used to be — it works out perfect."

Mike Scanlon, president of the Self Storage Association, said the storage industry's busiest time is from spring through fall when people are most likely to be moving, though there is a bump in business around the holiday season.

"There's not many places to hide that stuff around the house if it's a bike or some kind of sporting good item, things you just can't hide in the back of a closet," Scanlon said.

"Businesses also store extra inventory. They're gearing up for the shopping season, and they may only have room for so much."

Even storage facilities that don't offer Santa specials are pretty sure their customers have figured out the holiday angle.

Joanne Fried, spokeswoman for U-Haul, one of the largest storage companies in the U.S. with more than 357,000 units, said customers already renting units also stow their Christmas gifts there.

"I'm sure some people who are already in the units use it for that purpose," Fried said. "It just makes it easier on them."

The storage unit industry has nearly doubled in size over the past decade, with close to 40,000 storage unit facilities nationwide.

One in 11 households currently rents a self-storage unit compared to 1 in 17 in 1995. Self-storage facility gross revenues for 2005 were about $18.5 billion, according to the Virginia-based Self Storage Association.

"They treasure these items and keep them for a reason, but they don't want them underfoot," said James Overturf, spokesman of Extra Space Storage, which operates over 425,000 units in the U.S.

Hiding gifts is just another way to use the space they are paying for. "We've had focus groups in the past who say they use them to store Christmas gifts and other holiday decorations," Overturf said.

Terri Sibbett and her husband manage A-A-A Storage in Nashville and recently posted a listing at craigslist.com that asks, "Wanna keep the Christmas gifts away from those sneaky little ones?" It offers to "Hide the toys from the kids. Hide the boat from your husband."

The idea for promoting the storage units as holiday hiding spots came from A-A-A Storage headquarters in Austin, Texas. The company has close to 30 locations in Illinois, Florida, Tennessee and Texas, Sibbett said.

Since Nov. 1, Sibbett's location has offered customers seasonal rent discounts — 25 percent off the first month or four months for the price of three. The smallest-size storage unit is 5 feet by 5 feet and costs about $32 a month.