Her first claim to fame was the Katrina Cottage, a modular kit house offering temporary-to-permanent shelter for hurricane victims. Now designer Marianne Cusato is back at the drawing board and hammering to resolve a different crisis – "McMansion refugees" struggling to stay afloat in the aftermath of the credit crunch.

"We are seeing a paradigm shift in how we build and what we build based on necessity and circumstance," says the Miami-based designer, noting that demand has spiked for smaller, more-efficient, modestly priced houses as over-leveraged buyers learn to live within their means.  Enter the New Economy Home, a concept that acknowledges this new reality.

Adaptability is the operative word in Cusato's first "new economy" prototype.

Measuring a modest 1,500 square feet, the four-bedroom, three-and-a-half bath dwelling is outfitted with two possible masters – one of which is a ground-floor annex that can function as part of the whole house, or break off into a private suite or income-producing apartment. 

In good times, that suite might be used as a family room, office, or guest bedroom, Cusato explains. Whereas in tighter times, it can be closed off and rented out to help offset the mortgage, or occupied by a cash-strapped adult child, an elderly parent, or one member of a divorcing couple if the separating parties can't afford to support two households. The flex suite includes its own private outdoor space and entrance, as well as a large closet that can be rough plumbed at minimal cost and later retrofitted into a kitchenette. 

Overall, the prototype seeks to do more with less in a footprint measuring 24 feet wide by 50 feet deep. It's chock full of space savers, including a kitchen electronics recharging station, an entry vestibule with a storage bench and coat hooks, and a powder room tucked under the stairs to eliminate dead space and max out the building footprint. Wet areas are aggregated for centralized plumbing to simplify construction, reduce mechanical runs, and lower water consumption. 

For this venture, Cusato has partnered with building scientist Mark LaLiberte, as well as housing affordability expert Fernando Pages Ruiz. Cusato stresses, however, that the big idea isn't about affordability so much as efficiency and flexibility. "Building an efficient home may not be the cheapest thing you can do," she says, "but it is the most valuable thing you can do." 

Her goal is to engineer an introductory plan that can be built for less than $200,000, not including land costs. The first prototype is set to debut this spring, with additional single-family and multifamily designs in the works. All plans will be created to work in both infill and TND settings.

Jenny Sullivan is senior editor, design, at BUILDER.

Learn more about markets featured in this article: Miami, FL.