Five Models of Energy Efficiency: A Guide to Beautiful, Energy-Efficient Homes
Five US builders are being honored for their exceptional achievements in high performance building at the second annual BASF Builders Challenge Awards.
Led by the U.S Department of Energy (DOE), the Builders Challenge is working with homebuilders across America to build a new generation of high-performance homes, working toward the ultimate goal of providing cost-effective, net-zero energy homes by 2030 for all Americans.
To qualify for the Builders Challenge, homes must meet at least a 70 on the EnergySmart Home Scale (E-Scale) — which means they must use at least 30 percent less energy than a typical new home built to code.
2010 BUILDERS CHALLENGE AWARDEES
Colorado Builder’s Net-Zero-Energy House Costs Just 7% to 8% More
Ecofutures Building Inc. developed four certified Builders Challenge homes (two with minus-three HERS ratings). These net-zero-energy measures represented only 7% to 8% of the total building cost.
Artistic Homes of Albuquerque offers a net-zero-energy upgrade option on all their homes. They’ve completed and sold 11 true net-zero-energy homes ranging from 1,305 to 2,905 square feet and costing between $160,000 and $300,000.
Tim O’Brien, a fanatic about eliminating air infiltration, actually got $400 back from the utility the first month after construction was finished. He guarantees a zero energy cost for the first 5 years on his home.
The right roof is essential to designing an environmentally friendly and energy-efficient home. If you’ve got typical shingles or hot asphalt on your roof—as many homeowners do—you could be doing better. Below are a few cutting-edge roofing techniques that can cut your energy costs and make your house greener at the same time.
Use recycled shingles. If you want an environmentally friendly roof, the worst thing you can do is install 15-year, non-recycled shingles. These are among the most disposable building materials, are hardly ever recycled, and contain toxic volatile organic chemicals that evaporate under the heat of the sun. This means that just by sitting under the sun and heating up, your home is releasing toxic chemicals into the air. For a greener option, use recycled asphalt shingles that use reclaimed materials, reducing waste. These shingles often have a 50-year lifespan instead of 15, so you won’t have to replace them as often.
Consider metal. Metal roofs are more energy-efficient than shingles. Metal roofing is typically made from aluminum, copper, or steel, and you should ensure that your roofing is lead-free. Metal does not have the kind of heat-absorption qualities shingles have, so it will absorb and radiate less heat into your home. In fact, the right color metal will actively reflect sunlight, keeping your home cooler in hot summer months when the sun is most intense. Metal roofing also stands up to the elements better than shingles typically do—it’s the best for rainwater catchment systems, and snow slides off it easily.
Reflective coatings. To make your shingled roof more energy-efficient, brush a reflective coating on. Uncoated shingled roofs typically absorb around 80% of the sunlight that hits them—heating your home in the summer and driving up your air conditioning bill. A coated roof, however, can reflect about 80% of heat—giving you significant energy savings.
Clay and slate. Two natural materials that make excellent green roofing choices, clay and slate are both energy-efficient, can be disposed of without pollution, and are much less toxic than shingles. Corrugated clay tiles encourage air flow on the surface of the roof, keeping the home cool in the summer. However, hail will shatter it, which is why it’s typically only used in warmer climates. Slate is far more durable—it can last up to 100 years with minimal maintenance. Slate can also be reclaimed and recycled.
Building-integrated photovoltaics (BIPV). This is a roofing system that’s coated with a film that converts sunlight into electricity—a solar-power coating for your roof. This system uses tiles or shingles, and the electric current flows on the edge of the roof. The tiles look like slate, and can be installed by most roofers—an electrician will also be needed to hook the solar-energy system up to your home’s electrical system. The charge it generates isn’t huge—about 1 kilowatt of energy per 100 square feet of tile
Roof turbines. Companies in the Netherlands, Scotland, and Britain are developing small turbines designed to install on roofs and convert wind power into home electricity. The turbines are typically around six feet across, and are usually mounted on the roof or a pole. Roof turbines feed energy into a converter, which transforms it into electricity for home use. They can typically provide enough power to operate lights, a refrigerator, a television, and a computer—providing significant energy savings. However, the amount of energy an individual house sees will depend on how windy its location is
There’s growing interest in living roofs or green roofs. The difficulty is deciding on the waterproof membrane. Rubber pond liner (EPDM) is the most waterproof and durable material, and the most common choice due to proven performance, but it’s also very expensive and made from nasty petro chemicals.
Living roof at Heartwood Homesteads
I think a number of less toxic, more affordable materials are possible, including recycled materials in good condition. One reader suggested pool covers. Heavy duty trucker tarps are another option. You could add 6 mil poly (plastic sheeting) underneath and/or above these other materials for extra moisture protection.
For my dome, I used 2-1/2 layers of 6 mil black poly and have had no leaks so far after about three years in a rainy climate. (The half layer is a small piece on the very top.) You need to cover 6 mil poly carefully to avoid punctures. Some use old carpet or cardboard against it while adding soil. (Screen out rocks.) In our case, we simply packed soil on the plastic, starting at the bottom and working up, with no protective cardboard, etc.
Recycled vinyl billboards are another possibility, but I wouldn’t use them because of the health hazards of leaching chemicals into the soil around the house.
Roof pitch is another consideration. Steep roofs shed water faster and are less prone to leaks. But you need to strike the right balance or top soil and nutrients will wash away, and your roof will dry out too quickly.
Another consideration is the value of the structure. It’s no big deal experimenting with alternative waterproof membranes on a simple $2,000 guesthouse. But you might want to use better materials or multiple layers on expensive homes.
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EPDM Rubber Roofing – The Flat Roof Solution
Due to inflexibility, weathering and failing joints, sooner or later conventional flat roofing methods will leak. If you have been struggling with a flat roof leak, or you have a flat or gently sloping roof project, you’ll be excited to discover EPDM rubber roofing. With billions of square feet installed, EPDM has been proven to give many years of leak free service. Best of all, it is simple to install yourself.
Flatroofsolutions.com is the only company dedicated to Do It Yourself residential and smaller commercial applications of EPDM roofing. Since our start in 1993, we have helped thousands of customers solve their flat roof problems. We sell
Roof-Top® EPDM and adhesives and accessories. Everything needed for application, including a installation DVD that takes you step by step through the installation process. We even have EPDM for your RV rubber roof. Our friendly, knowledgeable sales staff is available to answer any question and help you with your materials purchase.
If you would like to learn more about EPDM rubber membrane, please click on About EPDM at above left. If you would like to know more about the installation process, please click here.
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