Sometimes it’s not what’s on the walls, but what’s in them that makes a home stand out.

That was the case last month at the unveiling of the New American Home 2014, an annual demonstration of the latest in residential design and construction.

The showcase house was on display as part of the recent International Builders’ Show in Henderson, Nev., and can now be toured virtually by visiting

The 6,706-square-foot house will eventually be for sale in the $5 million range, according to architect Jeff Berkus.

Unlimited Digital Access. $1 for 4 weeks.

The home is somewhat subdued-looking outside with a color scheme drawing from the desert landscape.

But the residence shines in ways that aren’t visible, such as the spray-foam insulation hidden in the walls that helps make it the most energy-efficient demonstration home constructed in the 31 years the National Association of Home Builders has been hosting such projects.

The builder “took it to heart when I told him he needed to build an aboveground submarine,” says Drew Smith, an energy and green-construction consultant on the endeavor.

The result is a contemporary design with a stone-veneer exterior that appears vaguely pueblo or adobe in style. What the two-story house at first seems to lack in outward pizazz it makes up for in practicality.

The low Home Energy Rating System number of 22, Smith says, is partly the result of hybrid insulation that in some areas is moisture permeable and in others creates an air and water barrier. Other factors include smart siting, overhangs, solar roof panels, high-efficiency windows and LED lights.

The house also uses less than half the water of a standard home and is surrounded by regionally appropriate landscaping. Green and sustainable building materials reduce off-gassing, or that “new house smell,” Smith says.

The launching point for the home’s design was its intended purpose as a multigenerational residence, Berkus says.

A double-island design in the kitchen plays into the idea of extended families living together — it can seat eight comfortably or a slew of studious children with textbooks spread across the counter.

“Our approach was to be mindful of family living, [and] to allow the occupants to be connected,” says Mark Tremblay of Marc-Michaels Interior Design, based in Winter Park, Fla.

Beyond the common areas are more private spaces that encourage independent living. A second-floor suite includes a small kitchen and living space as well as a bedroom and bathroom. Accessible by an elevator, it could be used by elderly parents, adult children or live-in help.

Recycled construction-site lumber was sanded and stained, then stacked vertically on the stairwell wall. The different widths created a textured effect.

A bedroom accent wall was created using standard decorative moldings cut at 45-degree angles into footlong pieces and applied in a chevron pattern.

The reaction to the home has been unexpected, says Josh Anderson, president of Element Building, the home’s builder.

“People come through touching the walls and fabrics,” he says. “They experience the home in a different way. It’s tactile.”