The 92nd Street Y announced yesterday that it is leaving the Upper West Side, selling its townhouse there in order to raise funds for a major renovation of its flagship facility on the Upper East Side. The Y plans to relocate its West Side programs to another location within the next two months.

The philanthropist Michael Steinhardt purchased the building at 35 W. 67th St. in 1997 and in 1999 turned the former residence for young Swiss women into Makor (meaning “source” in Hebrew), a music, film, and educational center aimed largely at single, Jewish New Yorkers in their 20s and 30s. Five years ago he donated Makor to the 92nd Street Y, which added daytime programming for baby boomers and named the building the Makor/Steinhardt Center.

Now the board of the 92nd Street Y is looking to the valuable property to help it finance a major improvement to its main location at 1395 Lexington Ave., which it said would take place in the next three to five years. Plans are in the early stages but the idea is to create a separate entrance and rooms for the Makor program.

“Serving the population of Makor has become a priority for the entire institution,” the executive director of the 92nd Street Y, Sol Adler, said.

The move caught the Steinhardt family by surprise. “The Y was sure in a hurry to sell the building,” the former chairwoman of the Makor/Steinhardt Center board, Sara Berman said. Ms. Berman, who is Mr. Steinhardt’s daughter, said, “I would expect a cultural institution as established as this one to have a more fully developed plan, especially as to what comes next for Makor.”

Ms. Berman, who writes a weekly column for The New York Sun, also questioned the appeal of the 92nd Street Y building to the younger crowd Makor appealed to. “I don’t know anyone in their 20s and 30s who would look to go out and have a great time on 92nd and Lex.”

A senior vice president at CB Richard Ellis, the real estate company that is handling the sale, Tim Sheehan, said the property is unusual because it sits on a double-wide lot and from the time it was built in 1904 has never been used as a private home. The facility currently has a lecture hall, screening room, and music lounge. Neither the Y nor the broker would give an asking price, but industry sources say the building could fetch as much as $25 million.

The interim Makor will be located downtown, in Midtown, or on the Upper East Side, but patron Adam Bronstein said he had trouble thinking of it anywhere but where it started. “I’ve always felt that its location is part of its identity,” Mr. Bronstein, a financial researcher, said. “It’s a nice building that reflected its mission.”

Mr. Steinhardt, an owner of the Sun, was on a plane to Israel and could not be reached for comment.