When architectural designer Rocio Romero was asked by her parents to design and build a low-cost beach house in Laguna Verde, Chile, she delivered an elegant, light-filled jewel box--for around $35,000. "I realized I could have saved even more by building it as a prefab," Romero says. So she founded a company, Rocio Romero LLC, to sell her own prefab homes.

Last year, Romero and her husband, Cale Bradford, moved into her first prefab creation, a 1,150-square-foot two-bedroom cottage. Her company makes kits starting at about $33,000, which covers the structural elements of her floor plans--beams, wall panels, and metal siding. (Customers hire a contractor to assemble it and add the rest.) Though Romero conducts her own R&D by living in her design and uses it as a show room for clients, she still considers it her haven. "We always schedule vacations," she says, "so that we can spend at least part of them at home."

The Materials
"The exterior is Galvalume, recyclable steel sheets coated in a zinc-aluminum alloy. For our home's interior we used gypsum board. We went with a Pergo floor because it's easy to install."

The Construction
"This was the first prefab home I designed. I was having trouble getting local manufacturers to take me seriously, so I said, well, if they won't pay attention to me, I'll build it. So I rented a manufacturing facility, set up shop, and I assembled the panels myself."

The Light
"All the large windows at the back of the house face east. We don't have curtains, so we rise with the sun. First thing, the sun is in our bedroom waking us up. Because there is so much natural light, I'm more aware of where the sun is."

The Man's Touch
"My husband, Cale, collects '50s and '60s memorabilia, jukeboxes, and political propaganda. But he likes the simplicity of the space. He's the first one to say, 'Okay, this just doesn't work here.' There's a ton of stuff in storage. His gas station pump, I don't know if we'll ever find a place for that."

The Air
"I built this house the same year we got married. We had only lived together as a married couple for one year, in an apartment in St. Louis. It was awful. For half of the summer the air conditioning didn't work. Cale insisted we get an air conditioning system for this house that was twice as big as what we needed."

The Lavatory
"I used clerestory windows to bring sunlight in, so I don't need artificial lighting in the daytime. I also used stainless steel fixtures and cabinets. It is sleek and clean, and it makes me want to treat the bathroom like a living space."

The Aesthetic
"Living in a modernist environment makes you picky with respect to what you have. I threw out a lot of old clothes when we moved in. I think it's liberating."