Monday, May 4, 2009


The heating, cooling and lighting of our buildings accounts for 48 percent of all U.S. energy consumption. As such, building energy usage is the greatest contributor to green house gases and global warming. This will only increase as the world becomes more urbanized and the built environment represents a greater and greater portion of our environment. Stormwater runoff from buildings is also one of the greatest non-point sources of water pollution, while the manufacturer of synthetic materials used in the construction of buildings leads to hazardous waste and an increasing number of "sick" buildings. Following is a discussion of methods of constructing "green" buildings so as to promote a more sustainable environment.

Green Roofs

Green roofs are one of the most visible ways to build more sustainable, "green" buildings. A study conducted for Toronto, Canada estimated that the installation of green roofs on buildings could: reduce the heat island effect of urban areas by 1 to 2 degrees C, reduce smog alerts in cities by 5 to 10 percent, absorb CO2 emissions from automobiles and thus reduce green house gases, reduce the energy needs of buildings for heating and air conditioning, filter storm run-off and thus reduce water pollution, and expand recreational and open space in urban areas by creating roof-top gardens.

Solar Photovoltaic Panels

Solar photovoltaic panels are used to convert the sun's energy into electricity. A converter is used to convert the electricity from DC to AC electricity. Any excess electricity can be stored in batteries or exported to the electrical grid and sold to the local electrical utility.

Solar Hot Water Systems

Solar hot water systems are systems that absorb the heat of the sun to heat water for the use within a building.

Passive Solar

Passive solar is any means to use the heat from the sun to provide for the heating or energy needs of a building without any means of mechanical assistance. The easiest method of passive solar involves the proper siting of a building to take advantage of the sun when it is at a low horizon or angle, but to provide shading when the sun is at its highest during the hottest part of the day. Another means of passive solar design is to build the floor of a building with some type of thermal mass such as concrete that absorbs the heat - and releases the heat at night when it is cooler.

Wind Turbines on Buildings

Previously, wind turbines as an energy source were typically not located on building or within urban areas. With the concern about green energy and global warming, however, new technologies have recently been developed to allow wind turbines to be built on top of buildings -- and be able to deal with the shifting wind directions typical of urban areas. These new wind turbines are omni-directional and come in sizes appropriate for individual homes and larger buildings. As such, wind turbines are increasingly a part of sustainable green buildings.

New "Green" Building Materials

"Green" buildings can be built from a variety of new eco-friendly building materials. This includes what is perhaps the most common form of new building material -- insulated concrete forms (i.e. ICF) - as well as more exotic new building materials such insulation made from recycled jeans or recycled newspapers to replace the traditional fiberglass insulation used in homes or renewable bamboo wood floors.