"Green" building is becoming mainstream. Faced with escalating energy costs, increased awareness of the depletion of our natural resources, and the ill-effects of poor indoor air quality, a movement is growing among building industry professionals and homeowners to approach residential construction with a primary view toward energy conservation, alternative energy generation, and the employment of sustainable, non-toxic materials. This is the first Article of a multi-Article series summarizing the various quidelines currently in the marketplace and analyzing how they can be applied in the context of the renovation of a brownstone or other urban townhouse.