We hear that a penthouse at the Upper West Side’s Ardsley — a pad adjacent to Barbra Streisand’s former digs — is on the market for $20 million.

Unlike Streisand’s old apartment, which has no park view, this one faces it and apparently feels like a townhouse “hovering 22 floors above Central Park,” according to the listing.

The Emery Roth-designed Art Deco building at 320 Central Park West briefly gained fame when the co-op board rejected Mariah Carey’s application after she showed up for a board meeting in an outre outfit back in 1999.

The five-bedroom, 4½-bathroom apartment comes with two massive terraces that have unobstructed views — and are big enough for large-scale entertaining and to plant trees, according to the listing.

It’s the first time the co-op is on the market in 30 years.

The unit comes with 15-plus-foot ceilings in the dining room, library and living room, the latter of which features a woodburning fireplace.

There’s also an eat-in chef’s kitchen that opens onto one of the terraces.

Building amenities include a gym and library.

The listing brokers are Stribling’s Alexa Lambert, Merrill Curtis and Marc Achilles.

We hear that Ian Schrager, Harry Macklowe, Liz Diller, Christopher Sharples, Robert Couturier, Thom Filicia and more will be at the 92nd Street Y for “City of Tomorrow,” a real estate, architecture and design summit created by Robin Dolch, founder of Hundred Stories, the luxury real estate PR, marketing and events company. The summit runs from Friday, Feb 3 to Saturday, Feb. 4.

We hear that Joe and Kristen Farrell of Farrell Building Company and Douglas Elliman’s Andrew Azoulay are hosting a launch party on Feb. 9 to celebrate “Hamptons on Hubert,” a new Hamptons showroom in TriBeCa at 11 Hubert St.