As heavy, wet snow blanketed New York City last month and then quickly turned to slush, the sidewalks in front of some luxury apartment buildings remained pristine. As if by magic, snowflakes melted as they touched the ground in front of these upscale addresses, releasing a faint vapor that hung momentarily in the bitter cold before vanishing altogether, thanks to what is turning out to be the ultimate amenity in an unrelenting winter: heated sidewalks.

“It’s a big plus for us,” said Peter Kostoglou, a well-groomed doorman in a double-breasted overcoat at 535 West End Avenue, where the heated sidewalk is going on its third winter. “It cuts the work down.”

He paused to open the door for a high-heeled resident who strode briskly across the glistening pavement to a car waiting by the curb, seemingly oblivious to the slush nearby.

The stiletto-clad aren’t the only ones who enjoy the warm walkways. “The doggies love it,” Mr. Kostoglou said, noting that there is no need for salt, which can be irritating to tender paws. Meanwhile, across the street, at 530 West End Avenue, the sidewalk was equally clean, but the doorman and superintendent were nursing sore backs from shoveling. “It’s 11 a.m. and we are already tired,” said the doorman, Orlando Caraballosa. “We wish we had it.”