Stepping onto the cool champagne marble floor in the octagonal foyer of the seven-story townhouse at 58 E. 66th St., you can’t imagine you’re going to feel at home. ¶ But wait — is that red gingham in the dining room and flea-market art in the stair hall? This year, 22 of the nation’s top designers managed to make a posh $35 million 1909 mansion look glamorous as well as, yes, a bit homey. Even the $250,000 Christopher Peacock trophy kitchen has a warm vibe with its burled elm counter and custom-built Nespresso coffee capsule storage drawer. ¶ “It’s a very livable house,” says Jamie Drake, designer of the foyer, whose client roster includes former mayor Michael R. Bloomberg. He commissioned burgundy walls that twinkle with mica dust and a ceiling dotted with floating cloudlike light sculptures. ¶ Welcome to the 2015 Kips Bay Decorator Show House, the nation’s most prestigious annual showcase for interior design. The designers who were selected had about eight weeks to complete their rooms, and the show house opened Thursday for a month-long run. ¶ Located in the Lenox Hill neighborhood, the 9,600-square-foot Beaux-Arts-style townhouse was built by architects Buchman & Fox for Arthur Sachs (of investment firm Goldman Sachs).

It’s a good address. Andy Warhol used to live across the street.

The house has just been totally renovated for resale to reflect the lifestyle of today’s gazillionaires. There are five original fireplaces with gorgeous mantels. The oval staircase is perfect for grand entrances. Five generous bedrooms all have their own sumptuous baths; in some you will find state-of-the-art Kohler toilets that come with remotes to use for flushing and other purposes too personal to mention. A 27-foot lap pool is under construction.

Remember, they call it a “show” house, so some things are a bit over the top, even for the 1 percent.

This is Kips Bay’s 43rd year, and a new book, “40 Years of Fabulous: The Kips Bay Decorator Show House” by Steven Stolman, chronicles the memorable rooms over the years. There are spaces that become instant legends and are talked about for years in design circles.

This year’s visitors may be chatting about two memorable rooms across from each other that are rich in fabrics, textures and the color red: the dining room by Mark D. Sikes and the living room by Alessandra Branca. Italian-born Branca’s living room is chic and relaxed, with lots of vibrant red print fabrics. “It reflects both energy and practicality,” she says.

Remember the red dining rooms of the 1980s? This is nothing like those stiff, lacquered, overly formal spaces full of mahogany antiques. Sikes, who is based in Los Angeles, lightened the dining space, which he outfitted with cushy banquettes in a red Soane Britain fabric called Fez Stripe, trimmed with bullion fringe. Upholstering red gingham, exotic paisley fabrics and silk trim on the walls, he made the room feel dramatic yet cozy. The dining table and chairs are rattan from Sikes’s own collection for Soane.

“Nobody wants a formal dining room any more. Sure, I wanted to create a show, but I think this room would still look great in 20 years,” Sikes says.

Alessandra Branca’s vibrant living room. (Rafael Quirindongo)

Mark D. Sikes’s dramatic but cozy dining room. (Rafael Quirindongo)

Charles Pavarini’s “Midnight Manhattan” lounge is the kind of high-drama room Kips Bay is known for. It has a lighting control system with iPad-based dimming and curtains made of embossed shagreen leather. The walls’ shimmery blue color was based on Pavarini’s own lapis ring. Pavarini says to get the effect he wanted, Farrow & Ball paint was mixed with iridescent blue eye shadow powder. No word on whether it was Maybelline or MAC.

Toronto designer Philip Mitchell hung 250 pieces of art, salon-style, winding up several floors of the home’s classic staircase. He calls it “a curated collection of art pieces that reflect what I love.” The pieces don’t have matching frames (a recent designer obsession) and come from different periods. There are paintings, photographs, etchings, sculptures and porcelains. The mix of family pieces, flea-market finds and high-end works create a striking focal point. Just keep your hands on the bannister; it’s a long way down.

Instead of the stately library or ubiquitous media room that seem to be staples in show houses, designer Thom Filicia did a modern study that can be used for tweeting and working as well as having a few friends over for drinks. You might remember him from his design gig on the Bravo series “Queer Eye for the Straight Guy.” A neutral space, it has a desk and a seating area with brass, bronze and leather accents. See if you spot the orange cashmere throw and Creel and Gow candleholder of black-and-orange sea urchin; the touches of orange are a nod to his alma mater, Syracuse University.

The espresso Lambourne cabinetry of Peacock’s kitchen is a rich contrast to all the white and gray kitchens that have populated the pages of design magazines lately. A slab of live-edge English wych elm spills over the center island.

“It looks very organic, like it’s growing out of the counter,” Peacock says. The cabinets are fitted with satin brass hardware.

“I’ve gotten as far as I can with white kitchens and polished nickel hardware, which put my kids through college,” Peacock says. “I like this new sophisticated and elegant look.”

The 2015 Kips Bay Decorator Show House can be viewed May 14-June 11 at 58 E. 66th St. in Manhattan. (Brown Harris Stevens)

Kips Bay DecoratorShow House

Open daily through June 11 in New York. Admission is $35 and benefits the Kips Bay Boys & Girls Club. For more information, call 212-755-5733 or go to