The recent and increasing attention being paid to green or sustainable building offers many benefits to the housing industry and homeowners. At the same time, it reinforces and renews the value of a comprehensive approach to land-use planning and housing design.
The notion that a whole can be more than the sum of its parts is an especially apt phrase for green building. While there are several land-use and building practices, product and systems applications, and materials that qualify as green, it is the concerted and thoughtful integration of those "parts" that enable a markedly higher standard in housing performance and resource efficiency.
Consider, for instance, a home sited on an east-west axis to optimize the path of the sun. To gain those benefits, the home's design-build team would likely incorporate well-placed windows and a corresponding thermal mass, such as a tile floor or brick fireplace, to enable passive solar heat; in turn, that design reduces the burden on the home's mechanical heating system, saving the energy to operate it and extending its usable life.
Next, think about the domino effect created by advanced or optimum value framing techniques. In a sincere effort to build green, the framing package is likely to include as much engineered lumber as possible, which not only reduces the amount of lumber required (given its long-span and higher design-load capabilities), but also makes more efficient use of forest resources than traditional sawn lumber; engineered wood also is less likely to warp in application, meaning a tighter structure with less thermal transfer.
Advanced framing methods further reduce the amount of lumber (and thus forest resources) needed for the structure while creating wider cavities for insulation. In turn, the use of blown-in, recycled-content cellulose in the walls and ceiling or attic framing and air-blocking expanded foam insulation on the underside of the roof sheathing, with an air/moisture barrier wrapping the shell, create a tight structure that results in a steady indoor climate, reducing the load on the heating and cooling equipment and the energy to run it.
Furthermore, by insulating the attic and creating a semi-conditioned space that is within only a few degrees of the living space below, the mechanical equipment and (insulated) duct runs can be placed there, instead of in a space-hogging closet within the floor plan, with minimal thermal loss and more durable, high-level performance. In addition to its role as an air barrier, a properly installed housewrap blocks and sheds unwanted moisture away from the framing members, mitigating the potential for mold and structural degradation that can impact indoor air quality and the home's overall performance.
Finally, look at lighting. Once again, a house positioned to maximize what the sun's path provides is ideally designed to take advantage of daylighting opportunities through thermally efficient windows, skylights, translucent panels, and glass blocks. Doing so reduces the amount of energy needed for artificial lights, which are, ideally, fitted with compact fluorescent bulbs to lessen their energy impact even more.
A comprehensive, systems approach to residential building quickly reveals a whole host of relationships among land use, construction methods, materials, and products that, when integrated properly, result in the high-performance homes that truly reduce the environmental footprint of the built world.