Adam Larkey, ABC The crew on "Extreme Makeover: Home Edition consists of, from left, Michael Moloney, Constance Ramos, Ty Pennington, Preston Sharp, Tracy Hutson and Paul DiMeo. Click photo for larger image.

Home makeover shows have come a long way since TLC's "Trading Spaces" burst onto the cable TV scene four years ago. That show's $1,000 makeovers, completed by two designers and a handful of helpers in a mere 48 hours, seem almost quaint these days (especially, that is, in comparison with the mammoth tear-downs featured on "Extreme Makeover: Home Edition," the ABC show that debuted last December as a special and quickly catapulted to the top of the ratings).

Now in its second season, this hourlong unscripted reality show features whole-house renovations that cost hundreds of thousands of dollars and would normally take months to complete, were it not for the crew of 100 or more working feverishly 'round the clock for close to a week.

But it's more than the scale of the project that sets this show and others apart from their predecessors. "Extreme Makeover" seeks families with hard-luck stories, such as a recent episode about a single mother who was taken by a home-improvement con man. Another show, Fox's "Renovate My Family," extends the renovation idea to counseling and self-improvement for family members.

If ratings are any indication, home improvement with a heart is a hit.

"It's really a show about doing good things for deserving people," says Tom Forman, executive producer of "Extreme Makeover: Home Edition."

One recent episode featured a man from South Central Los Angeles with four young children who took in his five siblings after their mother was killed by a gang member's stray bullet.

On "Renovate My Family," the crew, from left, is made up of the Dahm triplets, Scott McCray, host Jay McGraw, Kathi Lee and Jude Alcala. Eric Liebowitz/ABC Click photo for larger image.

"These people did good in their community, but for one reason or another, something went wrong," says Forman, who also served as screenwriter and producer for the award-winning CBS documentary "9/11." "It's not just about people whose house needed some help."

Likewise, "Renovate My Family," which airs at 9 p.m. Fridays, "is about people whose American dream has stopped and need some kind of help getting back on track," says executive producer Ray Giuliani.

In one episode, for example, the crew builds a new house for a family of five who lost their home and dog in a devastating fire. In another, a couple's only son has been in a snowboarding accident that has left him in a wheelchair with a 50-50 chance of walking again.

In helping these families, Fox's approach is a more comprehensive and, arguably, just a little cheesy: In addition to a renovated and redecorated house, each contestant gets a physical makeover (new hair, new clothes). And because all of the families featured are in some kind of "emotional state," they also get advice from self-help author Jay McGraw, son of renowned relationship expert "Dr. Phil" McGraw.

"When we tear down their house, it's a symbol of a new beginning," says Giuliani. "They learn to address some of the problems in their lives and to look at their family in a new way."

Both shows differ from series such as "Trading Spaces" and its spinoffs such as "While You Were Out" in that the designers actually talk with family members and design something they like and often need. A woman with lung cancer, for example, gets a home with easy-to-clean surfaces and air filters. The family whose house burned down is surprised with a backyard batting cage for their baseball-star son as well as a chance to play catch with John Smoltz of the Atlanta Braves.

In one episode of "Extreme MakeoverHome Edition," more than 150 workers rebuilt the Ali family's home in Queens, N.Y., two years after a contractor left them without a roof. Ty Pennington shows the results to Lucy Ali and her 12-year-old adopted sons, Paul and Kuran, right, who had been hop-scotching from hotel to hotel, to relatives' couches and to a homeless shelter. Click photo for larger image.

It's an experience that, despite the wonderful rewards, requires some faith.

"Everyone watches and thinks, 'Wow, they're getting a whole new house,'" says Giuliani. "But it takes trust to walk away from your most valuable asset and put yourself in the hands of people you really don't know well."

Part of these shows' appeal, no doubt, is the "wow" factor. It's fun to watch 100 people smash a house to the ground, then transform it into something out of House Beautiful in a week's time. (Permits and approvals are secured beforehand and building inspectors are on the set 24/7).

There's also the requisite eye candy: "Extreme Makeover" is hosted by former "Trading Spaces" hunky carpenter Ty Pennington, and "Renovate My Family" boasts the Dahm triplets -- Nicole, Erica and Jacklyn -- former Playmates turned construction workers.

But mostly, it's the sincere, feel-good stories -- you can actually watch these shows with your kids -- that draw viewers. ....."It's the right show for the weird times we live in," Forman says. "People are looking for things that remind them they can make a difference."

The formula is obviously working. "Extreme Makeover," which airs at 8 p.m. Sundays, is watched by an average of 15.7 million people each week and is tied for 18th place in household ratings this season with "Law & Order: SVU." The show has so far renovated 26 homes and receives about 1,000 applications a day.

"Renovate My Family" has somewhat less spectacular ratings: It is tied for 84th in household ratings, with 5.1 million viewers.

The TLC show that started the home-remodeling reality show craze in 2000, meanwhile, has seen its ratings slump considerably in the past year. "Trading Spaces," which is currently shooting its fifth season, has even changed its format. But it may be too little, too late.

Host Jay McGraw and Ashley Reimer discuss the new look for her and her family on an episode of Fox's "Renovate My Family." Eric Liebowitz/ABC Click photo for larger image.

Jon Hein, founder of www.jumptheshark.com, a Web site devoted to the decline and fall of America's favorite television shows, says one of the first signs of a show's impending doom is the spinoff. "Trading Spaces" has spawned two: "TS: Family" and "TS: Boys vs. Girls."

A "very special" episode is another indication the show is headed south.

"Remember the Las Vegas special?" says Hein. "That highlighted just how overexposed it had become. It was a great idea when it started, but I think it got caught up in its own hype."

"Extreme Makeover: Home Edition," which is itself a spin-off of a show about cosmetic transformations, is also sparking imitators. NBC is currently developing its own show with Latrobe-born producer Bob Kusbit of One Louder Productions. Called "Home Intervention," it will feature homeowners who have become trapped -- sometimes for years -- in huge, uncompleted renovation projects. It will showcase the talents of designer Vern Yip, who rose to fame on "Trading Spaces."

Unlike the other two shows, which whisk contestants away on vacation or to therapy while construction is under way, these homeowners will do much of the work themselves.

"We'll make them finish what they started, so they can prove to the world and themselves that they can do it," says Kusbit, who also created the series "Made" for MTV. He said the show is now looking for contestants, as are the other shows.

Forman says it's gratifying to see that reality shows don't have to be about competitive eliminations, voting people off islands and other "mean-spirited stuff." Who knew America would respond to nice shows about fixing up nice people's houses?

"We can't change the world, but we can give people a helping hand and make their lives a little easier," he says.

For information or to apply:

"Extreme Makeover: Home Edition" -- www.abc.go.com/primetime/xtremehome.

"Renovate My Family" -- www.fox.com/renovatemyfamily.

"Home Intervention" -- www. nbc.com/nbc/footer/Contes-tants.shtml.