Watch an animation from ASLA’s Designing Our Future: Sustainable Landscapes online exhibition that explains how to use the landscape to reduce the energy consumed by a typical suburban home. See how smart tree placement and green roofs and walls dramatically improve energy efficiency.
Trees are being cut down to make way for new single-family homes, which then often sit on bare lots. These treeless lots not only have negative impacts on the climate, environment, and community health, but they also exacerbate the energy inefficient practices found within homes. This is a major problem given the average American home consumes 70 million BTUs annually. In fact, taken together, American homes account for 22 percent of total energy use as well as nearly 22 percent of carbon dioxide emissions (1.19 billion metric tons).
(Source: The Washington Post and Architecture 2030)
McKinsey & Co, a management consulting firm, found that energy use in the U.S. could be cut by 23 percent by 2020 by implementing simple energy efficiency measures. While homeowners can take low-cost steps to make the inside of their homes better insulated and therefore more energy efficient, the landscape isn’t often seen as a part of the problem… or the solution. Basic green technologies like smart tree placement and green roofs and walls can be used to dramatically reduce energy usage inside homes. If placed strategically, trees can reduce summertime cooling energy needs by 7-47 percent and wintertime heating needs by 2-8 percent.
(Source: The Washington Post and Reducing Urban Heat Islands: Compendium of Strategies. Trees and Vegetation, U.S. E.P.A.)
In addition, well-designed residential green roofs, which are growing popular in some parts of the world, can reduce energy usage in both summer and winter. According to one Canadian study, a 32,000-square foot green roof on a one-story commercial building in Toronto reduced energy usage by 6 percent in the summer and 10 percent in the winter. Similarly, the green roof of the American Society of Landscape Architects (ASLA) at just 3,000 square feet reduces energy usage by 3 percent in summer and 10 percent in winter. Weather, roof, and building size and location also have an impact on the amount of energy savings. Lastly, fast-growing green walls can also reduce energy use by providing insulation in the winter and limiting direct sunlight on walls in the summer. In hotter months they also cool air temperatures by up to 10 degrees.
(Source: Reducing Urban Heat Islands: Compendium of Strategies. Green Roofs, U.S. E.P.A. and American Society of Landscape Architects (ASLA) Green Roof)