Green Building, What, Why, and How? (Tapestry magazine, March 2007)
Rising energy costs, global climate change, and growing environmental ethics are changing the way we build.
What is “Green Building”?
There are currently dozens of programs, local and regional, that set minimum standards for green building. Some areas have none at all, resulting in a patchwork across the country of sometimes conflicting guidelines. There is no single definition. There are, however, some common themes.
- Site work must minimize its environmental impact both during and after construction.
- Using recycled materials and materials whose production can be maintained without harming people or the environment.
- Healthy indoor air quality. (IAQ)
Why build Green?
According to the U.S. Department of Energy (D.O.E.) construction and maintenance of buildings is responsible for 40% of U.S. energy use and 30% of wood and raw materials. Buildings are also major contributors to global warming, generating 30% of U.S. CO2 emissions.
With rising utility costs in the headlines, many, (if not most) people are looking for ways to save on their monthly utility bills. By using green building principles in the design and construction of a building its energy use could be cut by as much as 50%. Additionally, the use of sustainable, renewable, and non-toxic building materials reduce the environmental impact of a structure on society as a whole. According to the D.O.E., if one house in ten incorporated an energy efficient heating/cooling system in conjunction with proper insulation, we would prevent 17 billion pounds of air pollutants. That is equal to taking 250,000 cars off the road.
Through the use of proper ventilation , the reduction or elimination of toxic materials in the structure provides healthier indoor air quality for the occupants.
Green buildings can also require less maintenance and repair, thereby reducing long term costs to the homeowner.
How is it done?
Siting: Green building includes where the house is placed. Choose a site to take advantage of solar access and winter wind protection. Save where possible and plant when needed, trees for shade in the summer and wind blockage in the winter. Locate the structure away from environmentally sensitive areas. Disturb a minimal amount of the site during construction.
Energy Efficiency: A tight building envelope and energy efficiency are key elements. House design and orientation should be used to maximize solar gain and natural lighting. Use high efficiency lighting. Use properly sized heating /cooling systems tied to a properly insulated and air tight building envelope. The ENERGY STAR® program is a great place to start. Use a rater to create a computer model of your building’s energy use through the ENERGY STAR HOMES program for new homes and the HOME PERFORMANCE Program for existing homes.
Water Efficiency: Water conservation is also important. Water saving and low-flow fixtures are what most people are already familiar with. Plumbing fixtures are available that can be used to minimize the waste of hot water. It is also possible to include rain water collection as well as “grey water” systems that recycle water from showering and washing.
Material Choices: First of all, reduce the amount of material used in the structure by building a house that is no larger than it needs to be. Choose construction materials that are renewable and sustainably harvested. Use those materials effectively through careful construction techniques such as designing on a 4’ grid that minimizes waste of standard material sizes. Evaluate the materials you choose based on such qualities as used or recycled content and low to zero off-gassing of harmful chemicals into the building. Choose materials based on durability and longevity as well as maintenance required. Don’t forget to consider what materials can be provided from local resources to reduce transportation needs. While choosing materials, keep in mind not to let it dominate other factors such as energy efficiency and IAQ. A building that is built with all green products can still waste energy.
Indoor Air Quality: Energy efficient houses are tight houses. But tightly sealed houses can trap a variety of indoor pollutants. Improving (IAQ) has several related steps. The choices made to remove materials that off-gas harmful chemicals are an important step toward good IAQ. Guidelines can include closed combustion appliances that draw combustion air from the outside and maintain a separation between combustion air and indoor air. They also include bath fans and range hoods vented to the outside to remove contaminants at those sources. Some homes may use whole-house ventilation systems with heat-recovery equipment to reduce heat loss.
What About Costs? Green building does not necessarily cost more. While some estimates say that there can be a 3-10% premium, those advocates also point out that to solely look at the initial cost is misleading. It is more accurate to look at costs over the life of the building. The choices of durable, low-maintenance materials and a properly sealed, well insulated shell mean much lower operating costs to the homeowner over time. According to a recent article in the Wisconsin State Journal (Dec. 31, 06) about Tom Eggert , The cost of his green home addition was $75 per square foot , half of the average cost for his area.
Finally, a green building cannot achieve its goals unless it works as intended. This includes testing and adjustments of all mechanical systems as well as proper care and maintenance by the occupant. Remember, the homeowner is an active part of the green building system.
This quick overview has hopefully given you an idea of what green building is, and what it can do for all of us.
David Romary owns Hearth & Sol Construction and Energy Services in Viroqua, and has been building both standard and green homes for 25 years. He is also licensed through RESNET to provide household energy ratings under the ENERGY STAR Program.