GETTING PRACTICAL: ENERGY DETAILS THAT BUILDERS CAN LIVE WITH The best details balance tricky theories with common sense As a quality engineer for Acorn Structures, I travel regularly to construction sites to see how builders are making out with new energy-saving building techniques. Invariably, the innovative concepts and products we read about in the magazines get refined as they are adapted to the realities of the building site. Following is an off-the-top-of-myhead list of some current theories on energy performance, and how I've seen them reshaped in mainstream building practice. The purpose is not to prove the theories "right" or "wrong," but to demonstrate that a judicious balance between what's optimal for energy performance and what's practical to build leads to the best overall results. Foundation Insulation Theory: Exterior rigid insulation is superior to