Indeed, they are only occasionally at home. Mr. Levin, 53, teaches architecture at Parsons School of Design at the New School and Ms. Betts teaches architecture at Columbia and Cornell.
The rest of the time they are busy running their firm, LevenBetts, from an office overlooking the High Line, a few blocks from home. There, they frequently design much larger, provocative structures, like an 8,000-square-foot beach house in Amagansett, N.Y., with three wings that cantilever out from a concrete-and-glass base.
But such grandiose living isn’t for them. When they found their current apartment, a long, 12.5-foot-wide rectangle of space in a prewar building that was cut up by interior walls, they relished the challenge of transforming it into a hyper-efficient home.
“We like to find funky places we can mess around with,” Mr. Leven said.
“With this one, it was: How do we make this feel like our old loft in terms of organization and openness” — despite the reduction in size, Ms. Betts said.
For a total cost of about $60,000, they worked with Rachel Chaos, a contractor, to gut the apartment, paint every surface white and build a black box at the center containing the bathroom, with cabinets wrapping the outside. Clad in MDF doors coated with Danish oil, to create a steel-like appearance, the box functions as a kitchen pantry on one side and bedroom storage on the other, with general storage in between (including a nook large enough to hold a bicycle).
At the back of the apartment, a bank of white floor-to-ceiling cabinets covered in crisscrossing pencil lines — a Sol LeWitt-inspired work by the artist Allan Wexler, a friend — separates the bed from the entrance door.
“It’s a riff on Thomas Jefferson’s bed at Monticello,” Mr. Leven said. “Jefferson had the bed between two rooms; we have it between a cabinet and a wall.”
For the living room, they designed a low Baltic-birch bookcase that does double duty as a bench, with felt pads on top.
In the kitchen, they installed a custom dining table with a sanded acrylic top that provides enough space to have friends to dinner, but is within arm’s reach of the range and under-counter refrigerator.
“The great thing is that you can take the food out of the oven while sitting at the table,” Mr. Leven said, leaning over from a chair to demonstrate.
In such tight, stripped-down quarters, every object matters, Ms. Betts added.
“We like elevating the ubiquitous, and curating everything from the artwork to the kitchen pantry,” she said, pointing to a stainless-steel shelf lined with matching glass jars containing oats, pistachios, pine nuts, black bean noodles and squid ink pasta. Put on display, these kitchen staples become decorative items.
Living in such a pristine space, however, has its challenges. The painted wood floor, as white as baking soda, inevitably collects urban grit. To keep it looking fresh, the couple has their contractor repaint it every six to nine months.
That constant painting could be seen as the ultimate luxury or an extreme inconvenience. But for Mr. Leven and Ms. Betts, it’s simply part of realizing a larger vision.
“You would never think of a loft-like apartment being in a building like this,” Ms. Betts said. “It’s a small apartment, acting big.”