Buildings and Cities
Heat always moves from warmer areas to cooler areas, until a temperature equilibrium is reached. This heat flow presents a central challenge when keeping buildings within a desirable range of 67 to 78 degrees Fahrenheit. To close the gap on unwanted heat gain or loss and maintain comfortable room temperature, we use more energy. Air infiltration accounts for 25 to 60 percent of energy used to heat and cool a home—energy that is simply wasted.
By better insulating a building envelope, heat exchange can be reduced, energy saved, and emissions avoided. What makes insulation effective is its capacity for thermal resistance, measured as R-value—the higher the better. Ideally, a building’s thermal layer should cover all sides—bottom floor, exterior walls, and roof—and be continuous. Sealing gaps and cracks is also critical to a more effective building envelope.
Insulation is one of the most practical and cost-effective ways to make buildings more energy efficient—both in new construction and through retrofitting older buildings that often are not well encased. At relatively low cost, insulation results in lower utility bills, while keeping out moisture and improving air quality.
air infiltration…energy…wasted: St. John, Kathryn. “Building Green with Energy-Efficient Materials: Insulation.” U.S. Green Building Council. September 7, 2016.
range of insulating materials: Schiavoni, S., F. Bianchi, and F. Asdrubali. “Insulation Materials for the Building Sector: A Review and Comparative Analysis.” Renewable and Sustainable Energy Reviews 62 (2016): 988-1011.
waste feathers from poultry operations: Hickey, Shane. “The Innovators: Greener Home Insulation to Feather Your Nest.” The Guardian. April 10, 2016.
Passivhaus…saving energy: Trubiano, Franca. “Energy-Free Architectural Design: The Case of Passivhaus and Double-Skin Facades.” In Design and Construction of High Performance Homes, 37-54. New York: Routledge, 2013; James, Mary, and James Bill. Passive House in Different Climates: The Path to Net Zero. New York: Routledge, 2016.