Install energy-efficient windows

In addition to well-insulated walls, ceilings and floors, another key consideration for net-zero energy homes is efficient windows. Such windows may have double or triple panes with gas fillings and special coatings to help resist heat gain or loss. Specially constructed frames help seal against air leaks.

How the windows are installed in the wall is also important, since much of the heat loss can occur around the window rather than through it. Proper mounting and sealing of the window in the wall can help protect against air leaks.

"Installing windows for high energy efficiency can be tricky," says Jim Crowley, owner of Crowley Builders in Grass Valley, Calif. "If the window opening isn't right, it's like putting a round peg in a square hole; there are going to be gaps."

Crowley addresses this by using SIPs for the walls. "In addition to providing insulation, SIPs have pre-cut window openings that are straight, square and properly sized. Combine this with proper sealing of the window and it's the best way we've found to get a tight fit."