Japanese Developers Find Growing Interest in Homes With Solar Panels

When new trends in apartment living emerge, they often take hold quickly in fad-conscious Japan. That is what happened with “solar apartments,” residential buildings that have solar panels on their roofs. Now, such buildings are being aggressively promoted by some Japanese developers.

People here are enamored of new homes and apartments, and so are developers, who find them profitable — about two-thirds of houses and apartments bought and sold here are new.

Interest in solar apartments grew after the March 11 earthquake last year. The aftermath, which included a meltdown at one nuclear power plant after a tsunami struck and the shuttering of others, periodically deprived Japanese households of electricity. There were many calls for greater reliance on renewable forms of energy, including solar.

“Whenever the conditions allow, we want all our new apartments fitted with solar panels,” said Toshiya Kitagawa, executive officer at Takara Leben, a midsize apartment developer in Tokyo.

The company’s first solar apartment went on sale last June, in the city of Wako in Saitama Prefecture, near Tokyo, and sold almost instantly, according to the company. Takara Leben — like its rivals Sankei Building and Daikyo, which have developed similar projects recently — had conceived the solar-apartment idea before the earthquake. But the disaster “gave a big boost” to sales of the 112 units, Mr. Kitagawa said. The price tags were 30 million to 38 million, or roughly $350,000 to $470,000.

The company was so happy with the results that it now has five projects in the pipeline, two to be completed this spring.

Sankei Building, another midsize developer, had also set out to build a solar apartment in 2010 in Musashino, a popular suburban residential district of Tokyo. Last June, the company announced its sales to great acclaim. “They sold out quite instantaneously,” said Yukari Sasaki, the managing officer who heads the residential development department at Sankei in Tokyo. “People’s awareness for natural energy and disaster readiness has been greatly enhanced” after the earthquake.

Each apartment’s solar system comes with control panels and a display that compares energy generation and use on a month-to-month and year-to-year basis. The apartments also have batteries that kick in when grid-supplied energy is cut in emergencies. Sankei Building has three new solar apartment buildings in the works.

There is another reason midsize developers favor solar apartments. They tend to build on the outskirts of Tokyo, while their bigger rivals, like Mitsui Fudosan, Mitsubishi Estate and Sumitomo Realty, have an edge in developing inner-city high rises in prime locations. But high-rises are generally unsuitable for solar apartments, because they require expansive roof space relative to the number of units.

“The building shouldn’t be taller than five to six stories,” said Ms. Sasaki of Sankei Building. “You end up with too little roof space per housing unit.”

Sankei Building and Takara Lebel assigned six solar panels to each unit. “That’s the minimum, given the need to generate enough solar power to each household,” Mr. Kitagawa said.

An expensive lot in the city center that could fit a 30- to 40-story structure is a poor choice for solar panels. Besides, “You want be clear of tall buildings in the surrounding areas, which could compromise full exposure to sun you need to have,” said Hiroshi Iwamoto, sales manager for Takaka Leben’s solar apartments in Yokohama.

According to Takara Leben, the six panels per household for most of its apartments in Tokyo and Yokohama will be enough to cut electricity bills 56 percent in a typical household of four, based on a simulation conducted by the Tokyo Electric Power. According to the company’s math, the energy bill falls to 6,150 a month on average from 14,035 — to about $75 from $170.

Hiromu Sato, 37, an owner and a resident of Takara Leben’s solar condominium in Wako, said he did not necessarily believe the electric company’s calculations when he was considering buying an apartment.

“I thought that figure was kind of hype,” he said. But he found the savings warranted the claim. “I am quite comfortable saying we are saving in excess of 10,000 a month, compared to the bill we used to pay” at the last apartment he and his wife shared, which was considerably smaller than the 70-square-meter, or 750-square-foot, unit they now own.