Pine Street Inn has used some money from a $15 million donation gifted by the Yawkey Foundation in December 2021 to improve its women’s shelter in the South End, upgrading windows, expanding the lobby and giving the home a new name.

The Yawkey Foundation’s $15 million gift is the large single commitment in Pine Street’s 55-year history.

“We have been working on housing for a long time, adding 20 to 30 units every year – it’s just not enough to keep pace,” Pine Street President Lyndia Downie said Wednesday, moments after the Women’s Inn was renamed the Yawkey House. “This gift allows us to really scale up. … This is a real scale, and you start to have an impact on people who have the lowest incomes.”

Downie has her eyes set on achieving a “big milestone” this spring, when Pine Street is expected to reach 1,100 units of permanent housing.

Since receiving the donation, Pine Street has been in the process of creating 400 to 500 new units of permanent housing over five years, a roughly 40% increase in its total units. The expansion of its housing units is coming at a dire time as Boston continues to grapple with a flood of migrants and skyrocketing housing prices.

Pine Street’s housing programs come with highly-skilled, trained support staff who work with tenants in accessing medical and behavioral healthcare, job training and jobs, volunteer opportunities and more to help them remain safe, stable and housed.

Agency officials allocated a bulk of the $15 million gift toward 111 units in Back Bay, 140 in Jamaica Plain and 99 in Dorchester.

The JP project is replacing a Pine Street Inn warehouse/building, and the Dorchester effort is converting a Comfort Inn into affordable housing. The Back Bay endeavor came to fruition last year, with tenants taking up space at 140 Clarendon St.

Demand is high on the units, with many of them attached with rental assistance, meaning thousands of house-seekers are on waiting lists either through the city or state, Downie said.

“Even this isn’t enough,” she said, “but it’s a beginning.”

Officials from Pine Street and the Yawkey Foundation gathered at the women’s shelter Wednesday to celebrate Jean Yawkey’s 115th birthday by renaming the facility in her honor.

Yawkey, who owned the Red Sox for over 40 years with her husband Tom Yawkey, “began personally funding Pine Street Inn in 1988, with a special commitment to supporting the critical needs of women facing major life challenges,” officials highlighted in a release.

More than 1,300 women receive support each year through Pine Street’s street outreach, shelter, workforce development and permanent supportive housing.

“We understood after the years that we’ve worked with them that there really needed to be flexibility in their ability to go out and find housing,” said Maureen Bleday, CEO of the Yawkey Foundation. “No two situations are really the same … so far it’s worked, we are in the midst of this.”

Mayra DeJesus has been a guest at the women’s shelter since November 2022 after her grandmother died in 2022 and she became nervous about the impact staying with her daughter would have on her grandson.

DeJesus has completed Pine Street’s housekeeping training program, and she said she plans on moving into the organization’s new housing complex in Jamaica Plain this spring.

“I am so excited by the idea of starting fresh in a new place,” she said. “I would also like to give back. I think about returning here one day to share my story to give hope to others.”