Unfortunately, the build cost is estimated at $600-800k. I'm more interested in the (presumably cheaper) insulation technologies than in the solar panels. See here for energy usage by housing type; a significant chunk of total US energy consumption goes to heating and cooling buildings.
Atlantic Monthly: ... NIST believes that this home – with 10 kilowatts of photovoltaic panels on the roof, and another four solar thermal panels over the front porch – will generate as much energy as a four-person family can consume in a year. This is, in other words, a “net-zero” house.