“It was important for me that it not just be your typical model apartment,” Ms. Behun said. “I understand how they try to speak down the middle to a more common denominator, because you don’t want to offend. But that wasn’t interesting to me.”
It also wasn’t of interest to the developers.
“We really wanted to stand out,” said Jill Cremer, the vice president of marketing for Macklowe Properties, which developed the building with CIM Group. “We were ready for someone like Kelly to come and respect the architecture, but also bring an unconventional, unique style.”
Ms. Cremer and her colleagues aren’t alone. As developers face a glut of newly constructed apartments, both condominium and rental, some are turning to interior designers and letting them run wild with model units in an effort to differentiate their buildings from the rest.
Newly built inventory for sale in New York was up 19.6 percent in the first quarter of 2017, compared with the same period last year, according to the appraisal company Miller Samuel. At the same time, Citi Habitats New Developments expects 15,291 new market-rate rental apartments to become available this year in Manhattan and Brooklyn, following just 8,774 units last year.
“There’s a lot of competition,” said Jonathan J. Miller, the president of Miller Samuel. “So getting eyeballs on those projects is important.”
At 520 West 28th Street, the condo building designed by Zaha Hadid, the Related Companies tapped the interior designer Jennifer Post to furnish a $15 million apartment as a model unit. Ms. Post brought in Bernhardt Design lounge and dining chairs with mismatched upholstery, added graphic yellow-and-gray wallpaper to one of the bedrooms, and stocked the unit with eye-catching art, including an explosive geometric painting by Allan D’Arcangelo, and a sculptural free-standing penguin from Robert Kuo.
“I took a risk, and burst it with color, art and energy — it’s not tone-on-tone,” Ms. Post said. “It was a great opportunity to be given the freedom to make something people will talk about.”
“We didn’t hold back anywhere in this building, in terms of creating something that’s never been seen before,” said Greg Gushee, an executive vice president of Related. “With the model, it’s the same thing.”
The development company DDG has been partnering with New York’s cutting-edge contemporary design stores to furnish its model units. The $2.435 million apartment used as a model unit at the Standish at 171 Columbia Heights in Brooklyn was designed by Matter, and includes a spidery copper pendant lamp with a pink-and-aqua glass shade by Bec Brittain, primitive oak dining stools and a table by Jamie Gray, and layered pink and turquoise living room curtains.
At XOCO 325, at 325 West Broadway in Manhattan, DDG invited Colony, a cooperative showroom for emerging designers, to outfit a $17.5 million penthouse. The resulting design includes textile wall hangings by Hiroko Takeda, a snaking 13-foot-long chandelier by Allied Maker and bold geometric tables by Fort Standard and Erickson Aesthetics.
“We try to push the envelope on design,” said Joseph A. McMillan Jr., the chairman and chief executive of DDG. “Having something that’s fully neutral or monochromatic is not something that we subscribe to.”
For homeowners who have frequently been told they should rid their homes of personality in order to sell, model units with such expressive design elements may seem counterintuitive. Indeed, some real estate professionals urge caution.
“From a marketing perspective, there’s certainly something intriguing about bringing out a very aggressive design from a well-known or up-and-coming interior designer,” said Stephen G. Kliegerman, the president of Halstead Property Development Marketing. “On the other side of that coin is the conversation about not being so specific as to potentially turn off a buyer who might not be as creative, imaginative or liberal.”
To appeal to the largest pool of buyers, he said, “we recommend that developers use fine, elegant, but more neutral palettes.”
However, with so many properties on the market, some designers and developers say spirited model units can help make buildings more memorable.
“Through color and personality, and non-vanilla spaces, we’re setting the things for people to remember,” said Dan Mazzarini, a partner in the interior design firm BHDM, which designed five model apartments at the Ashland. The 585-unit rental building at 250 Ashland Place in Brooklyn offers studio to three-bedroom apartments ranging from $2,675 to $7,500 a month.
One of the model units has dazzling colors and patterns, including walls with painted trompe l’oeil paneling, powder-blue ceilings and counter stools, and a purply pink tie-dye rug.
“When renters are going around to all these new buildings, they’re seeing maybe 10 units a day and it’s hard to remember, from one white apartment to another, which they liked and why,” Mr. Mazzarini said. “So we built these memory points — it’s the unit with the pink rug, or the 12-foot sofa, or the hats on the wall.”
The interior designer Ken Fulk had a similar objective for three model units at Henry Hall, a 225-unit rental at 515 West 38th Street. From the Imperial Companies, the building has apartments ranging from studios starting at $3,350 a month to two-bedrooms starting at $6,995. Mr. Fulk equipped a studio with a four-poster bed with multicolor zigzag bed curtains installed in an alcove with matching wallpaper.
“Some people will love it, some people will hate it,” Mr. Fulk said. “But even if you don’t like it, you’ll remember it.”
Eric Birnbaum, a partner at Imperial Companies, added: “We wanted to take a position and create a brand. If you’re doing it right, in our minds, you’re going to offend certain people. But others will really like it.”