Meanwhile, the back of the plan is cut from the cloth of contemporary suburban home design, encompassing a 36-foot-long swath of space for the kitchen, eating area, and great room; a telescoping patio door creates a 15-foot-wide opening to an almost equally large covered lanai featuring a fireplace and a stand-alone barbecue grill. “This is a wide-open house,” says Thompson. “You could do whatever you wanted with some of these spaces.”
Even with all of these upgrades, KB Home discovered an affordable and marketable formula (sans the $60,000 or so it spent on an 8.75-kW PV array and a companion solar thermal system) that it will replicate and offer as an Energy Star– and WaterSense-qualified plan at Mabel Bridge, a new community near the concept home’s location.
The bulk of those cost efficiencies were found up-front by way of advanced framing practices that included plated roof trusses and wall panels fabricated off-site, building a one-story home on a slab foundation, and designing on 2-foot modules to more precisely order panel products and reduce cut waste during their installation.
Because of the tight shell it created, KB Home also was able to right-size the heat pump capacity from 5 tons to 2 tons, among other swaps that enabled a higher level of performance at a lower overall cost premium. “In green building, there’s a remarkable opportunity to put the puzzle together a little bit differently and make some cost shifts that make it affordable,” says Aaron Davenport, the regional building science advisor for Masco Home Services in Gainesville, Fla., who administers the Environments for Living program.
Still, Glance does not predict that KB Home will see a net-zero return on its investment in the concept home. “In today’s [lending] climate, I’m not sure you could get an appraisal for this house at $380,000,” he says, given the lack of comps for net-zero production homes in Orlando—or anywhere. But making back the money it spent to upgrade to the home’s high level of energy performance was not KB Home’s objective. “There are still challenges in achieving net zero in terms of cost,” says Glance, whose team pushed the energy envelope to find out what it would require, finding it could be done (for the most part) by its existing crews and trade partners. “As we continue to move forward as an industry, I think you’ll see the costs come down while consumer demand goes up, and at some point those two will merge.”
Rich Binsacca is a contributing editor for EcoHome.