PROVIDENCE — There is no running water or electricity yet. And visitors have to wear hardhats and climb over construction debris to get inside.

But make no mistake: the luxury condos being built on the upper floors of the new hotel tower next to The Westin Providence are for sale.

If only there were more buyers.

In the nearly two years since developers rode the real-estate boom into Providence, the real-estate market nationwide has fizzled. Now, the condo market in Rhode Island is showing signs of weakening.

The number of condos for sale in the state has climbed more than 140 percent since 2005, according to the statewide Multiple Listing Service.

At the current pace of sales, it would take about 11 months to sell all the condos currently on the market, compared with about 7 months a year ago, according to Suzanne E. Mulvee, a senior real-estate economist with the Boston firm Property & Portfolio Research.

Meanwhile, the median price of a condo in Rhode Island during the first quarter of this year fell nearly 10 percent, to $207,500, according to the Rhode Island Association of Realtors. By contrast, the statewide median price of a single-family house during the same period fell about 3 percent.

Real-estate economists caution that price shifts in a market as small as Rhode Island can be more dramatic because of a change in the mix of properties being sold. That said, condo prices are generally “more volatile,” Mulvee said, than house prices.

“In a home, it’s about: Are you on this side of a street or that side of a street? Are you on a corner lot?” Mulvee said. “Whereas with a condo, one is just like the other for the most part.”

Three major luxury condo developments are under way in downtown Providence, though one of the projects, at 110 Westminster St., has yet to break ground. The furthest along is The Providence Westin hotel tower, which is scheduled to open in July. The closings for the condo units are expected in October and November.

In other parts of the country, developers are delaying, scaling back or even canceling downtown condo developments, citing softening demand and rising construction costs. In Madison, Wis., for example, a planned 13-story condo tower was recently revamped as an 11-story hotel. And just last week, a major casino and condo project in Las Vegas was canceled after its developer pulled out amid a weakening market.

People may read those reports and wonder: could it happen here?

The question frustrates Nicholas J. Iselin, director of development and construction for Boston’s Intercontinental Real Estate Corp. The company, he said, is now dogging rumors about its two condo high-rises at Waterplace Park.

“We’ve heard the rumor that we’re going to do a condo tower and an apartment tower,” he said, “but that’s not true.”

Iselin said the company still plans to build 193 condos priced at $400,000 to $1 million. He declined to say how many units have been sold.

“I’d love to tell you we were all sold out and it’s great,” Iselin said. “If we sold a quarter of them” by the time the building opens, “that would be OK,” he said. “If we sold half of them, that would be great.”

With so many more condos on the market to choose from, prospective buyers are in no rush to buy — and developers have been forced to scale back their own expectations. The average selling time during the first quarter of this year stretched to 112 days, up from 85 days in the first quarter of last year, the association reported.

Condo sales in Rhode Island are up or down, depending on which data you look at. The Rhode Island Association of Realtors, which tracks sales through real-estate agents, reported that first-quarter condo sales are up 4.3 percent; The Warren Group, a real-estate research firm which tracks all sales, including those by owners, reported sales fell 3.7 percent.

The demand for condos in Rhode Island is driven by three major groups: aging baby boomers, working professionals and second-home owners, said Peter Francese, the director of demographic forecasts for the nonprofit New England Economic Partnership.

During the last two years, however, Rhode Island’s population declined by 11,300 people, according to census data. The sharpest decline has been among residents in their 30s, who make up a significant portion of first-time homebuyers. Affluent empty nesters might want to buy luxury condos — but only if they can sell their houses.

“Retired people can go anywhere, and they’re very price sensitive,” Francese said. “There’s lots of $400,000 homes, but there is almost nothing between $150,000 and $250,000.”

The Procaccianti Group, which is the developer of condos at The Westin, has hired a team of five real-estate agents from Residential Properties to market its condos. So far, 27 of the 103 units have been sold, said Ralph Curti, a real-estate agent for Residential Properties. But even most of those purchase-and-sales agreements, he said, were signed last year. Most of the buyers, he said, were from Rhode Island. The prices range from $400,000 to $2.5 million.

Yesterday, Curti escorted two women through the construction debris to a back elevator for the ride 17 flights up to view one of the two model units which opened to the public this month.

The elevator opens onto a construction zone. No walls. No windows. Only corridors of cement and steel.

But step inside the model condo and it looks as if people have already moved in. There is stylish furniture, art on the walls and a dinning room table with place settings. There is even a fake flat-screen TV.

Nancy Blackburn is a 64-year-old retired medical office manager with two adult children. She lives alone in a three-bedroom house she owns on Providence’s East Side.

“Very lovely,” she said, admiring the marble bath. “It is gorgeous.”

The conversation turned to the revitalization of downtown Providence. The art. The theater. The shops.

“There’s a lot to be said about living down here,” Blackburn said.

But she was not at all sure about the $957,900 price.

“I just don’t know if I’d be able to swing that or not,” Blackburn said.

larditi@projo.com