By William Hirsch
Green building is the catch phrase for the creation of houses that are energy-efficient and environmentally responsible in their design and construction.
I’m old enough to remember the first Earth Day in 1970 when we called green building and sustainable design “ecology.” While the names are updated, the principles are the same. Some technology has improved, and the motivation and popularity has strengthened, but the goal of designing and building houses that consume less energy to heat and cool, and demand fewer natural resources to build, particularly natural resources that cannot be replenished, is still what it is all about.
To me, there are four parts to building “green.”
- Design a house that uses less energy to heat, cool, light, and maintain;
- Use materials that consume less energy to produce and transport, are non-toxic, and can be recycled or safely disposed of when no longer useful;
- Use building products made from materials that are not limited in supply and are quickly and easily regrown, reproduced, and replaced;
- And use energy sources that are readily replenished and have an unlimited supply.
An energy-efficient home is one that, due to its design, naturally tends to stay at the right temperature, is better insulated, tight, and does not leak air.
An energy-efficiency home begins with its proper placement on the land. Consideration must be given to solar orientation – where the sun rises, sets, and is situated at midday. The design should factor in protection from the winter winds and natural ventilation from the summer breezes.
The crazy part is that positioning the house optimally with regard to the sun, wind, and shape of the land usually does not cost anything extra, except a bit of thinking. Yet much of what you read about green building and energy-efficient design says little about the siting of the house and the intrinsic energy-efficient characteristics of the building design. And it’s not rocket science. It is basically the thoughtful positioning of the house on the site and the arrangement of windows and roofs to let the house stay cooler in the summer and warmer in the winter, naturally.
Enhanced insulation is critical. Actually, insulation is relatively inexpensive compared to the cost of other parts of a house. And it pays the biggest dividends. Additional insulation will reduce the heat loss in winter and heat gain in summer just as a heavy coat keeps you warmer than a thin one.
Making your house tighter by reducing the amount of outside air that infiltrates through walls, roofs, doors, windows, and foundations is critical. Did your parents ever yell: “Close the door. We’re not heating the street.” Mine sure did. The sum total of the leaks in the typical house have the same effect as leaving one door open. If you want an energy-efficient house, close the door by limiting the air leakage with a tight building envelope.
Metal roofs with a ventilating air space, properly-sized roof overhangs that shade exterior walls, and even fan-induced attic ventilation, can greatly reduce air-conditioning needs by keeping your roof, walls, and attic cool without using much electricity.
Look for the Energy Star logo when choosing appliances and equipment. Energy Star is a standardized home evaluation system used to gauge the efficiency of a home. If you are seeking an Energy Star certification, you gain points by using Energy Star-rated appliances. Getting an Energy Star rating could possibly earn you a lower electrical rate and a tax credit. Check with your power company and tax advisor on this.
Use materials that consume less energy to produce and transport, do not contain off-gas toxins, and can be recycled or safely disposed of when no longer useful. Green building is a holistic approach to design and construction. The so-called embedded energy involved with the manufacturing and transport of the building materials needs to be considered. Of course, products that last longer will probably be more “green” than those that have to be replaced frequently.
Look for locally manufactured products and materials. I always wince when I see those bottles of water that are imported from Fiji and wonder how much fuel is burned to bring me a bottle from the other side of the world that contains the very same thing I can get right where I live. The same holds true for your building products.
Did the manufacturing of the product use massive amounts of energy? The less energy used, the greener the product, with one major consideration. Some materials can be “green” while still requiring a lot of energy to produce. Bricks require high heat to make, but they have a long useful life and require virtually no maintenance. If bricks are unpainted, they can be recycled into other materials. Steel is similar with a long life and often is made from recycled steel.
Green builders use building products made from materials that are not limited in supply and are quickly and easily regrown, reproduced, and replaced. Concrete is made from earth’s virtually unlimited supply of sand, gravel, and cement. Clay and porcelain products are similarly “green’ so long as they contain no toxic materials that pollute during manufacturing.
We often hear about bamboo in this regard. It is a fast-growing plant that is being used in flooring, fabrics, and other products. But don’t overlook wood as a versatile “green” building material. Although no one likes to see trees cut down, trees do grow back. But select your sources for wood. Only wood produced in managed forests and harvested at sustainable rates qualifies as a green and renewable resource. Look for certifications of managed planting and cutting practices from organizations such as the Forest Stewardship Council (FSC) to be sure. One other “green” aspect to wood is that trees go a long way toward capturing carbon dioxide from the atmosphere thus helping reduce the increase in CO2 in the air.
Use renewable energy when possible. Photovoltaics, or electricity-producing solar panels, can provide all or part of your electrical needs, depending on your geographical location. Solar water heating and geothermal equipment may still use electricity to run, but at a lower rate than conventional systems. In some locales, excess electricity you generate beyond your consumption can be sold back to the power company for a credit thus cutting your electric bill.
In certain parts of the world, wind power can be efficiently utilized. While there is a high up-front cost with wind and solar systems, the payback is long. But the personal gratification from being environmentally responsible may be worth the added cost
Green building is the responsible way to build. Some green building methods cost little or no extra money to implement. Others cost money up front but can pay you back in a reasonable time frame. Others are too costly to be justified in economic terms, but you still might want them for the intrinsic benefit of being a good steward of our resources and our environment. Make your choices wisely.
Web / designingyourperfecthouse.com + about-home-design.com
William Hirsch, author of the best-selling book Designing Your Perfect House, is a member of the American Institute of Architects, the National Council of Architectural Registration Boards, and the former president of the Delaware Society of Architects.