Tiny house owners Greg and Renee Cantori discuss their 238 sq. ft. custom-made house. (Kenneth K. Lam/Baltimore Sun Video)

"In contrast to the manufactured-housing park, the tiny homes are typically about one-fifth the size, they've got gabled roofs, … they're designed and built by architects," Levy said. "And people, they stand in line for an hour to have a look. Calling a tiny-house community a trailer park is like calling Dupont Circle rowhouses tenements."

Tiny houses aren't the only example of small living. "Micro-apartments" of a few hundred square feet are popping up in some expensive cities, such as San Francisco, for young professionals who'd rather spend their free time downtown than in a sprawling living room.

Matt Hoffman, vice president of innovation at Enterprise Community Partners, the Columbia affordable-housing giant, said small dwellings aren't a solution for everyone. But they're a useful choice to have. More than 10 million people in America are "housing burdened," paying over half their income on rent, he said.

"We want to see a range of housing options for people," he said. "It's not a one-size-accommodates-all."

Part of the early drive for minimum-size regulations was to stamp out dangerous tenements, Hoffman said. But small doesn't have to mean hazardous.

"It seems like it's the right time to re-examine whether we can move back in a direction where smaller can accommodate people in a healthy and safe way," he said.

The cost for a tiny house varies. Coover, a workshop host with Tumbleweed Tiny House, said the company's ready-made homes sell for about $40,000 to $60,000. But people who buy plans, purchase materials at a home-improvement store and build it themselves — as in free labor — will probably spend $18,000 to $20,000, including appliances, he said.

One customer managed to keep the costs to just $5,000 by salvaging wood and waiting for great deals on other supplies, Coover said.

Of course, that doesn't include the cost of land to sit the house on. Some tiny-house folks buy. Some rent. Some find people with extra space they don't mind sharing.

In Cantori's case, it's sitting near his bicycle shed in his Pasadena yard. His actual residence isn't huge, either: just under 1,400 square feet for a family of four and their two dogs.

Cantori has spent his life in modestly sized places. At 19, he bought a dilapidated sailboat, fixed it up and lived there for nearly five years — all 180 square feet of it. His next move was to a studio apartment in Baltimore. Living cheaply has allowed him to pursue the nonprofit career he wanted, save money and go sailing on the side.

His tiny home was built by a lawyer from Kansas who intended to live there with his family of three. Then the family grew by one. So he sold to Cantori, who flew west with his brother two years ago, rented a U-Haul and drove back to Maryland with his new home hitched to the back.

For Cantori, the affordability of a tiny house is part of the draw, but also the ability to use less energy, take up less land and generally be "lighter on the environment." A 6,000-square-foot house not far from his neighborhood baffles him. Who would actually use that much space?

"The walk-in closet's bigger than our tiny house," he said.

His future retirement home is robin-egg blue, with a porch out front. Inside, there's a tiny stainless-steel fireplace, a closet and a combination washer-dryer. A table in the living room/dining area seats two, or up to five if folded out. The kitchen has an RV stove, microwave and small refrigerator. In the bathroom is a full-sized shower and a composting toilet. And up top, two lofts — each a bedroom.

Cantori thinks it looks spacious, thanks to high ceilings, white walls and 16 windows. There's just nothing superfluous inside.

"No wasted space," he said. "It's all about not wasting."