Global hot tub sales are starting to simmer, prompting spa makers to test new markets, according to a new report.

Industry analyst IBISWorld estimates international hot tub revenues will grow 7 percent this year, citing renewed consumer confidence and an improving — or at least stabilizing — economy. It also anticipates 13 percent annual growth to 2018.

Among the emerging trade areas: China.

The economy there is booming and the Chinese are traveling abroad in record numbers. They’re soaking up comforts in luxury hotels, which is driving demand for such products back home, said Peter Munk, the newly appointed president of Jacuzzi’s Global Spa Division.

“We just entered into China and have had great success there,” Munk said.

Economic uncertainties — and downright calamities, such as those seen in Greece — have cooled demand for hot tubs in many other regions.

“I think things are progressing in North America, but there is some weakening in Europe,” said Bob Lauter, president of the International Hot Tub Association.

Munk said he aims to strengthen Jacuzzi’s global strategy with an eye toward growing its market share in Europe. “It’s still an immature market and that gives us opportunities for growth,” Munk said.

Of course, Canada and Mexico are still the top trade markets for the United States. Canada accounts for nearly 5 percent of industry revenue, according to IBISWorld, based in Santa Monica, Calif.

So, what’s selling? Midrange and high-end products hold a lot of consumer appeal. “Those between the $5,000 to $10,000 range is where we’re seeing the growth,” said Brian Quint, president of Aqua Quip, a Seattle-based retailer.

Quint isn’t shocked to hear industry analysts anticipating steady growth.

“I think it’s probably not surprising to see some pent-up demand considering we’re coming out of an industry year bottom in 2011,” he said.

2011 was indeed a dismal year with hot tub revenues estimated at $865 million, down from $3.1 billion in 2007, according to IBISWorld.

“I think there is a certain demographic that is stepping up,” Quint added, “and I expect it to trend up over the next few years.”

That demographic is older and wealthier and drawn to spas for their therapeutic benefits.

“The industry trend is to grow that market because that’s good, solid growth,” as opposed to those who buy spas as a sign of affluence, said Chris Robinson, business manager at Lucite International in Cordova, Tenn., maker of acrylic spa surfaces.

Swim spas also are hot commodities. These recreational amenities account for about 13 percent of industry revenue, according to IBISWorld.

“We keep the colors fresh and the patterns and textures modern, maybe even avant-garde, some would say,” Robinson added. “This is a flashy product. It needs to have a bit of fashion to it.”

Lauter, who also is the CEO of Master Spas in Fort Wayne, Ind., just wrapped up a photo shoot for the company’s Michael Phelps Signature Swim Spas. The product is growing in popularity among aging baby boomers looking to stay active.

“This is the most affluent segment of society,” Lauter said. “It’s the perfect intersection of interest and income.”

Contraction also has been a boon to the industry. Many companies either closed or consolidated during the recession, and those that survived are all the better for it.

There are far fewer competitors.

“Doing business internationally is not only a revenue opportunity — it takes strategy, infrastructure, investment and staying power,” said Leo Hamacher, vice president of sales and marketing, international, at Watkins Manufacturing Corp., maker of HotSpring and Caldera Spas. “Some manufacturers may have realized that they were not prepared to make that investment during recent uncertain economic times and exited. Communicating in multiple languages is just the beginning.”

Only 56 spa manufacturers remain. That’s down from 100 in 2006, when the industry was at its peak, IBISWorld noted.

“What you have now is many manufacturers and very few brands,” said Munk, whose firm acquired ThermoSpas and Dimension One Spas in 2012 and 2013, respectively. “The economy gave us the opportunity to add two strong brands to our portfolio.”

“I think the industry should be pleased with some consolidation,” Munk added, “so we can deliver a better product to the end user and improve dealer profitability.”