As green building design matures, guiding principles can give form to the work. For example, over the past twenty years, the principle of “the building as a whole” has been developed in energy-systems design, emphasizing interactions among all aspects of a building, including envelope, lighting, heating and cooling, and renewable energy options. As another example, over the past ten years LEED has brought its own set of guiding principles that advocate balanced priorities in green design (site, water, energy, materials, and environmental quality); allowing the owner choice among these issues; and involving all stakeholders early in the process. Other guiding principles are proposed at the detailed design level: Consider daylighting, evaluate renewable energy, reduce water usage, and more.
This article explores a new principle to guide green building design, termed loosely “outside-in design.” A variety of benefits arise from designing from the perimeter of a building site and proceeding inward toward the center of the building.
Outside-in design suggests minimizing exterior loads and impacts, such as temperature effects, energy usage, water usage, wind, and noise. This is most effectively done by starting farther from the building and working inward. It is in some ways equivalent to solving a problem at its source rather than trying to solve a symptom. It is also similar to solving health problems by making prevention the top priority. For example, it is preferable to reduce air conditioning energy usage by shading windows on the outside and preventing direct summer sun from reaching the windows, rather than by only increasing the efficiency of the air conditioning system. Such shading further allows more substantial savings if the air conditioning system efficiency is then also increased. As another example, a line of trees provides a first line of protection against wind, allowing building weatherstripping, caulking, and other air barriers to be more effective and to last longer, since they will not be subjected to the higher pressures of stronger wind.
With outside-in design, community issues relating to a building's design are considered first, then site issues such as landscaping and vegetation. This is followed by consideration of the building footprint and overall configuration (stories, building type), then near-building features (shading, awnings, renewable energy collectors, etc.), then the outer envelope design (outer walls, windows, roof, foundation, etc.), then unconditioned spaces (attics, basements, attached garages, and sheds), then the inner envelope between conditioned and unconditioned spaces, then internal loads (lighting and appliances), and finally the comfort system (heating and cooling).