JUDY WOODRUFF: Cities across the country are struggling with a shortage of housing. But there are millions of spare bedrooms. As Stephanie Leydon from PBS station WGBH explains, Boston has become a launching pad for a new technology that connects people looking for affordable rent with homeowners who have space to spare.
STEPHANIE LEYDON: Before she started her graduate program in public health, Abby Herbst got a crash course in math. There are too few apartments for too many people in Boston.
ABBY HERBST, Graduate Student: I called actually a real estate agent. And they wouldn't take me as a client, basically, I didn't have the budget for a regular place. And I was looking farther and farther outside the city.
STEPHANIE LEYDON: But she found a place just a 20-minute walk from campus in this townhouse complete with a furnished bedroom, fully equipped kitchen, and the homeowner, Brenda Atchison.
BRENDA ATCHISON, Homeowner: We fell in together very well and very smoothly.
STEPHANIE LEYDON: They met online through a home-sharing Web site called Nesterly, designed to connect two generations with compatible needs: older people who want to stay in their homes, but need help.
BRENDA ATCHISON: Twelve-foot ceilings, it's a little hard to heat in the wintertime. So a little extra doesn't hurt.
STEPHANIE LEYDON: And younger people who need a place to live. Herbst pays $650 a month, less than half the cost of studio. And she does chores.
ABBY HERBST: Like, I take out the trash, the snow shoveling.
STEPHANIE LEYDON: The home-sharing idea came to Noelle Marcus while she was living in Boston.
NOELLE MARCUS, Founder, Nesterly: It was really, really expensive to find housing while I was in graduate school there.
STEPHANIE LEYDON: She's now based here in New York.
NOELLE MARCUS: I think the average one-bedroom in New York is over $3,000.
STEPHANIE LEYDON: Maybe worse than Boston.
NOELLE MARCUS: Worse than Boston.
STEPHANIE LEYDON: She says cities across the country face an affordability crisis fueled by the same trends: a limited housing supply and an aging population of homeowners.
NOELLE MARCUS: We have had over 6,000 people reach out to us from 280 different cities around the world and tell us that they want us to expand to their city.
STEPHANIE LEYDON: Which is her goal. For now, Nesterly is available in the Boston area only. People have always rented extra rooms in their homes, right? So why do they need Nesterly?
NOELLE MARCUS: Yes. So according to AARP, 40 percent of over 45-year-olds say they're interested in renting out a room in their home, but today only 2 percent are doing it. And we think that's because the right product and the right service didn't exist.
STEPHANIE LEYDON: Nesterly offers background checks, a payment system and ongoing support. A one-time housing aide to New York's mayor, Marcus sees the platform as way to ease the housing shortage and a problem that plagues old and young alike, loneliness.
ABBY HERBST: People don't talk about it a lot. And I didn't actually anticipate it before I came to college, but, like, I had never eaten meals alone in high school before. If I feel like a little bit lonely or like I want to talk to somebody, I just come downstairs and sit in the kitchen.
STEPHANIE LEYDON: Where she and Atchison both find a perspective they couldn't get from a peer.
BRENDA ATCHISON: And you just never know. You just never know what you're going to talk about.
STEPHANIE LEYDON: That older and younger people enrich one another's lives isn't a surprise to Noelle Marcus. She moved from Boston to New York mainly to be close to her grandmother.
NOELLE MARCUS: She's 89, and she's one of my best friends.
STEPHANIE LEYDON: An inspiration for a housing innovation that helps two generations under one roof. For the PBS NewsHour, I'm Stephanie Leydon in Boston.