It does not take a swami to foresee demand for energy and water conservation in housing as populations grow and supplies shrink, but the techniques for accomplishing that are less obvious. Builder Online's Nigel Maynard offers some.

No. 1 is seeing the house as a series of related systems. Efficient plumbing runs affect energy use, for example. Next on his list is more modular construction. He quotes Carl Seville, a Decatur, Ga., green building consultant, summing up the reason: "less waste, faster construction, fewer moisture problems"

Other techniques on the list include better air sealing, water systems that reduce demand and can reclaim at least some wastewater, Cheaper rooftop solar as roofing manufacturers get involved, and higher R-value windows.

Sticking with the energy-savings, the list has hybrid tank/tankless water heaters, energy monitoring systems and better ways to model energy use in designing homes.

And to get about as far back to basics as possible, agricultural wastes are predicted to find their way into several building materials.