When John Sweat first went rock climbing in Yosemite National Park, two things happened, he says. He fell in love with the sport, and he realized how convenient it would be if he could live in his car. Yosemite is a destination for an estimated 150,000 climbers each year, and a lot of those climbers, he noticed, stay on-site in their vehicles. "People there just brought their homes with them," Sweat, now 27, tells CNBC Make It. "Their whole home system is just geared towards being able to adventure." "Vanlife," or living out of your vehicle, has become a trend in the past few years as increasing numbers of Americans have downsized to save money and, often, to be more mobile. Both of these prospects appealed to Sweat. Last year, he had $2,300 in credit card debt and owed $8,500 in student loans. If he eliminated his housing costs, he realized, he could put more money towards getting out of the red. So a few months after his trip — around the time Alex Honnold went to Yosemite in his van and famously climbed the 3,000-foot granite monolith El Capitan without a rope — Sweat sold his Subaru. He left his apartment, took out a $12,000 loan to purchase a used 2010 Chevy Express 2500 and moved into the van. Here's why, for Sweat, embracing vanlife has turned out to be a great decision.

He's budgeting and paying off debt

Sweat's job is suited to vanlife. He leads backpacking trips as a wilderness therapy guide and works shifts that last up to weeks a time. Even when he had an apartment, between sleeping in the field when he was at work and traveling when he was free, he wasn't spending much time at home. "I had a two month stretch where I spent two nights in my apartment," he says. At his last place, his rent was only $215 per month, plus about $30 in utilities, because he shared a room with another guide who worked the opposite shift. Still, without that expense, and because he began budgeting, he's been able to save and start tackling debt.

The 2010 Chevy Express 2500 Courtesy of John Sweat

Since moving into the van, he's wiped out his credit card balance, paid back his mother some money she lent him, and trimmed $2,000 off his student loans. He's bulked up his emergency fund, so he now has $3,000 in the bank and $2,500 in a Roth IRA. And he's devised a plan to pay off the van, too, followed by the remainder of his student debt. Those loans are less urgent because they have a lower interest rate. He expects to be debt-free by the end of next winter. "I've spent most of my adult life feeling like I have a ton of money, or feeling really strapped and on the edge," he says. "Right now, I feel more financially competent and stable and well-set up than I ever have."

The 'secret' to living in the van

Just because Sweat resides in the van doesn't mean he's stuck there. "That's kind of the secret to living in the van: To not actually live in your van," he says. When he's not working, he goes hiking, watches movies in the library and plays music with friends. At least one day a week every off-shift he focuses on "adulting," which might entail returning emails, making sure his finances are in order or planning his next climbing trip. When he gets tired of hanging out at the library or a coffee shop, he has plenty of friends with wifi to spare. They're good for a shower, too, if the local recreation center is closed.

The bedroom Courtesy of John Sweat

"I have a strong community right now, and people are really generous with their space," he says. When he travels, he not only sleeps comfortably, but he eats much better than he used to. Instead of pulling over at a rest stop and having his pick of fast food chains, he'll cook something up on his three-burner stove, one the van's many amenities that he's installed or upgraded.

Vanlife is a process

"One thing I really like about the van is that it's a constant project," says Sweat. "I'm planning to remodel my kitchen soon." In addition to the stove, he's installed lights, charging outlets, and a water pump fed by a six-gallon jug, all of which are powered by solar panels he attached to the roof. To build the electrical system, he consulted with a friend who's an electrical engineer, and he did his own fair share of research, too. He has also put in some curtains, shelves and storage bins, as well as a full-sized bed that's big enough for him, though a little snug when he shares it. With the work he's put into the van, he estimates it's now worth closer to $17,000.

It's not always glamorous

There is a romantic appeal to vanlife, thanks perhaps to Instagram, where the hashtag has amassed a considerable following. "It's a one-word life-style signifier that has come to evoke a number of contemporary trends," reports The New Yorker, including "a renewed interest in the American road trip, a culture of hippie-inflected outdoorsiness, and a life free from the tyranny of a nine-to-five office job." Sweat's not too active on social media, though. "People post these beautiful pictures with them parked, and there's a sunset on the beach, and they're like, '#vanlife!'" he says. "Okay, that happens sometimes. But sometimes you get woken up out of bed by the cops." Once, when he was parked on a street in a town that didn't allow van-dwelling, the police knocked on his door and politely asked him to park somewhere outside of town. "I wonder if they felt bad for me, if they thought I was in the van based off hardship, which isn't true," he says.

The kitchen Courtesy of John Sweat

He usually tries to park at a friend's house, or to get lost in a sea of vehicles on the street, or to find a Walmart since, in his experience, they're welcoming to RVs and vans. Plus, they have readily available bathrooms. Another challenge when this time of year rolls around is staying warm. "If it's 19 degrees outside, it's 19 degrees in my van," he says. He tested out having a propane heater once, but it created too much moisture. His plan for now is to spend the harshest winter months at his girlfriend's place.

Overall: It's worth it