With the dollar at an all-time low, vacations in Europe might seem a hopeless dream for most of us, but many people have found a way to make them practical: home exchanges.

In a home exchange, you trade your house for one elsewhere, with no money changing hands except possibly for the fee for finding a partner.

Many residents of Napa Valley have tried the exchanges, and at least those we talked too are enthusiastic supporters. Admittedly, many  people aren’t comfortable letting strangers occupy their homes and even using their cars, but those who’ve done so report few problems.

A common way to arrange the deals is via Home Exchange (www.homeex change.com), a service that lists properties for trade. It now contains 20,000 listings all over the world, from San Francisco for weekends to Norfolk Island on the other side of the world.

Forty percent of the listings are in the United States, and that’s fine with John and Adele Baumgartner, who live in a spacious ranch home on seven acres on Big Ranch Road. They’ve traded in Florida, Dana Point and Coronado as well as overseas. “I like anywhere with sand and sun,” says John, a taciturn retired lawman.

His outgoing wife, by contrast, loves London and Paris.

They’ve traded more than a dozen times, and one of their biggest joys was the friends they’ve made, not just the people with whom they’ve traded, but others. In London on a trade, they met a yeoman of the guard at the Tower of London, and not only have been invited to private ceremonies there but also to stay in the private apartments.

They’ve also stayed in Henry VIII’s hunting lodge, a “truly amazing place,” and in a modest apartment near Copenhagen.

In Australia, they were on an island accessible only by ferry, and last summer they used a three-week stay in Belgium to visit all over Europe.

“Most Europeans have month-long vacations, and they want to trade for three or four weeks,” says Adele. “When we do that, we usually use the home as a base for two or three-day trips.”

John says, however, that he hasn’t been able to arrange some visits he’d like, such as to Brazil and Monaco.

They sometimes travel with friends or family — most homes can accommodate a number of people — and people who’ve stayed at their house have brought parents, children and even a nanny. “The kids loved the animals,” says Adele, who has let 4-H kids raise livestock on their spacious property. It also contains a working vineyard and is  within walking distance of three wineries.

Their house in nice, but not luxurious, and their son lives on the property, a big plus for the visitors as well as providing some assurance to the Baumgartners.

They say they’ve only had one complaint from a visitor; he felt it was too close to the road and its traffic, and his wife complained because the pool wasn’t heated. They left early.

On the other hand, the Baumgartners have been pleased with the places they’ve stayed, and felt they were fairly accurately described. In Denmark, they had only a part of the large home pictured, and the “patio with BBQ” turned out to be a hibachi but that wasn’t a big issue.

The Baumgartners have to arrange simultaneous trades, or find partners with more than one home, which is fairly common. Jack and Linda Cross have a home in St. Helena as well as one in Orange County; they bought the home here after an exchange at the Baumgartners inspired them, in fact.

Having two homes naturally gives them more flexibility, as they can lend out the “other” home if they can’t arrange a simultaneous exchange.

They have completed exchanges overseas in London, Dublin, Strasbourg, Mirepoix in Southern France — and an honest 15th century castle in Scotland. In fact, they’re doing a repeat for the Scottish Castle with the home in St. Helena.

“It was spectacular,” says Cross, who was there with his wife’s cousin and spouse. They even paid the in-house staff to prepare a banquet for friends while they were there. “It was like a Cary Grant movie,” he says.

Jack Cross says their first exchange was for a three-story Victorian townhouse in London. It required a short bus trip then a ride by metro into the center of London. Likewise, they stayed in a three-story Edwardian in Dublin a 15-minute ride from the center.

“It’s great to stay in a neighborhood with local shops, not be with all the other tourists. The neighbors are always very friendly, too.”

He’s tried to arrange a trade in Rome, but  he’s gotten notes back when he’s inquired that they’re only interested in renting at the time he requested, not a trade.

The Crosses fly with airline miles, and the Baumgartners have a son who works for an airline, so they can travel standby. Both couples have found a way to enjoy traveling at a reasonable cost in spite of the weak dollar.

The Crosses haven’t run into any real problems, but they admit that you have to be willing to trust people. “The people who do this are as much at risk as we are, but I spend six months communicating before the trade to feel comfortable with them,” says Jack Cross. “Everyone loves the idea, but few are willing to trade,” he admits.

Not surprisingly, Napa Valley is a very attractive destination for potential exchanges. Ed Kushins, the president of Home Exchange says, “Napa is a really popular designation.” He says the organization has about 50 members in Napa Valley out of the 20,000 listings.

He adds that members complete about 30,000 to 40,000 exchanges per year, and fewer than 1 percent complain. It costs $99.95 a year to sign up and list your home — and get access to those listed — and Kushins promises a free second year if you don’t arrange a trade.