Three different attic designs will be refined, tested, evaluated, and demonstrated in new home construction. The team will recommend the best of these approaches to home builders addressing cost-effectiveness and energy-efficiency. The baseline for comparison will be current energy efficiency code practices for attic construction involving ventilated, uninsulated attics containing code compliant ducts. The team will evaluate the new design approaches analytically at the start of the project. Researchers will assess approaches that include methods to produce sealed, insulated attics, as well as, standard vented attics, both of which have been demonstrated and are in limited use in the market today but currently add considerable cost to builders. The team will employ new and novel installation methods and materials that have the potential for energy savings on par with ducts in the conditioned space, but at a cost similar to current practice.