This note, GEN 31, originally published in November 1999, was reviewed by Peter Graham in August 2004. The information herein is considered contemporary and relevant. Why an EDG note on Teaching? Resource efficient design, that is doing more with less, contributes to decreasing the negative environmental implications of resource consumption. However, the environmental effects of buildings arise from the combination of many design and management decisions. Good environmental design and construction can avoid more than just the damage that flows from resource use. It is therefore important that building professionals learn how the many decisions they make can help create ecologically sustainable buildings, and this awareness begins in the classroom.