Home construction is turning green so rapidly, it is expected that a house soon will be so energy efficient there will be no need to tap the public supply. In mathematical terms: The energy a home is able to generate, sub­tract the energy required by the occupants, would be zero.

“Three main elements must co-exist for it to work cost-efficiently,” says Todd Blyth at Nudura, a manufacturer of advanced concrete wall forms. “Those components are: The ability to generate a constant energy supply; a building envelope with maximum strength and insulation; and an inside operation with reduced energy usage.

“If, at the outset, energy-impact decisions are made carefully regarding the walls, windows, roofing, ventilation and indoor climate control, you are well on your way to completely offsetting energy consumption. Once the building is erected, it’s a matter of smaller incremental decisions that add into the energy savings.”

This vision is already a reality. In 2010, the first “net-zero” school building will open in the United States, where it will showcase an important Canadian design element, as well as others.

• A roof with solar panels and electricity grid.

• Geothermal heating and cooling for environmentally responsible efficiency.

• Walls of concrete. The Nudura system is comprised of stay-in-place, pre-assembled blocks, steel reinforced, and then filled with concrete. It replaces traditional building methods. The durability and energy efficiency of concrete has shown to reduce energy costs up to 70 per cent. The entire structure (www.nudura.com) is reported to be up to nine times stronger, with far more fire protection and with far more sound insulation.

• Ventilation includes a CO2 monitoring system to keep good air quality indoors and allow no more outdoor air than necessary.

• Positioning is north-south allowing for effective day lighting (without glare) so that all artificial lighting can be off during 70 per cent of school hours.