photo by iStockphoto/Onur Döngel
Green Living
Filling in the Gaps
Tips for sealing up your home’s exterior shell for the greenest savings.

Your windows, walls, roof and foundation create what is known as your home’s ‘envelope.’ These components work together to maximize structural integrity and control moisture, temperature and air pressure, making you a comfy cocoon throughout the year. As the green building movement picks up speed, you should concentrate on these areas to realize the greatest payoff.


photo courtesy of Thermique
STATE-OF-THE-ART WINDOWS
Glass allows us to connect with the outside world while we’re inside, but it also steals from us in the process. In fact, 25 to 35 percent of the energy used in homes and buildings is wasted because of fighting heat gain in the summer and heat loss in the winter.

Low-e windows, consisting of two pieces of coated glass separated by a gas-filled air space, reflect heat, reducing heat transfer between panes of glass and improving insulation performance. “The ‘e’ in low-e, which stands for ‘emissivity,’ is the ability of a surface to radiate energy. Low-e coatings are rated for the amount of heat they radiate — the lower the number, the less heat is radiated and the better the insulation performance of the glass,” explains Bruce Lang of Southwall Technologies, manufacturer of Heat Mirror.

Generic low-e glass typically provides insulating performance of about R-4, while R-19-insulated walls are the norm. Bruce, who has definitely noticed the gap, says low-e glass may have reached the practical limits of its thermal performance and looks toward the cavity rather than the coating of windows for improved efficiency.

Revisions of window performance standards from Energy Star are scheduled to debut as early as 2009, and a couple of changes in the industry may meet the new standards: a triple-pane glass, consisting of three panes of glass and two low-e coatings, and suspended film inside an insulating glass unit. The first option raises the R-value from R-4 to R-9 but also increases the weight because of the third pane; the second option can create up to four insulating cavities, raising performance from R-6 to R-20.

A third alternative may be heated glass. Thermique manufactures windows that are UL-certified and code-compliant electrical appliances that supplement home heating systems, with 120-volt electrical lines that run across an invisible glass coating and conduct heat. You can adjust the window temperature up to 105 degrees using a dimmer switch.

“Glass takes away energy from the occupant’s body up to about 10 feet away,” says Thermique representative George Usinowicz. “Heated glass closes the ‘barn door effect.’ We have heated windows to a moderate temperature and with moderate wattage so you can turn down the thermostat when you’re using heated glass.” Because heated glass reduces condensation inside a building, it also reduces potential warping and rot to wooden window frames and possible growth of mold and bacteria.


photo by iStockphoto/Joe Belanger
SOLID WALLS
Different strategies can make your home’s walls more eco-friendly, from construction methods and materials to insulation.

Insulating Concrete Forms (ICFs) and Structural Insulated Panels (SIPs) are relatively new to the market but can be good alternatives to stick framing. “[The wall product] is airtight, energy-efficient and tornado-resistant,” says Mark England of AccuServ Building Supply, which uses ICFs. “It’s two layers of Styrofoam with concrete in between. It could range from 5 to 10 percent more on the cost of your home, but our customers are reporting 40 to 70 percent energy savings per month.” More than 75 percent of Mark’s customers are residential.

The framing industry is going through changes also, with businesses doing more pre-framing of walls in an environment that allows them to control the process, including waste. For instance, the biggest piece of wood Advantage Framing throws out is approximately four inches long because it uses 95 percent of what it cuts down, says Jim Humbert, company vice president and council member with Build Green Kansas City.

The combination lumber company, component manufacturer and house framer also does a lot of things to help insulate a house properly. It uses a ‘California corner’ to tuck insulation into a corner to help block air from coming in, glues exterior walls to the floor to help   minimize air loss where it’s most likely to escape and installs aluminum radiant barriers that can prevent heat from building up in    the attic. Advantage Framing also uses certified-forest plywood and floor joists with low levels of VOCs.

Well-performing insulation can make a big difference in home energy costs. Gerould Sabin, owner and president of Crossroads shop Elements of Green, is excited about his company’s latest insulation product, EcoBlue. Made of 75 percent recycled blue jean (cotton) fibers and 25 percent polyester, it’s easy to work with because no safety gear or breathing equipment is required and no special tools are needed. The product is also treated with a wet flame-retardant. “It’s the No. 1 product we sell,” he notes, adding a warning that you should avoid recycled blue jean insulation with boric acid used as a fire-retardant because it leaches out in three to five years.


photos courtesy of DaVinci Roofscapes
OVERHEAD PROTECTION
Topping it all off is the roof, which receives the brunt of the sun’s rays. You can try to deflect the heat with a metal roof or Cool Roof, using steel shingles like those offered by TAMKO that offer the classic beauty of slate, wood or tile. The thermal energy left that you can’t deflect can be diffused through proper ventilation.

As many roofing products are made with oil, you can green your roof by selecting materials that are more sustainable or recycled. DaVinci Roofscapes specializes in sustainable roofing products that are made of a pure thermal plastic olefin resin and come with a 50-year warranty, according to Wendy Bruch, DaVinci’s marketing  manager. “[The resin is] a byproduct from fuel, with fire-retardants, inorganic pigments and UV-stabilizers. Our roofs last two to three times longer than a traditional asphalt roof, and asphalt shingles require two to three times more oil to produce than DaVinci [products do],” she says. Since synthetic shingles are thinner than traditional shingles, they also weigh less.

When purchasing a roof, be aware of the longevity associated with recycled versus natural or manufactured materials. Look for a rating from the Cool Roof Rating Council, which requires that roofing materials reflect and absorb a certain amount of light in correspondence with the Energy Star program.


photo courtesy of CertainTeed
A BETTER FOUNDATION
Between the bottom of a house’s first floor and the property grade, your home could lose up to 60 percent of its heat from the basement area, or 20 percent of total heat that escapes from the home, says Dan Bromley, president of ABI Corporation, a foundation construction company. Most home foundations are not insulated, but ABI can install one of several insulation products as it pours new foundations.

“We use ThermaEZE Thermal Insulation System from CertainTeed [for above-grade, below-grade or shell construction insulating material] on the inside or outside of the foundation,” he says. “We use removable concrete forms for concrete basements and/or first floors, and I really like it for shell construction.” A thermal mass ‘sandwich’ wall, which includes a foam core with concrete poured on each side, may also provide insulation for standard foundation construction.

For added eco-friendliness, concrete can be produced with recycled materials that include cement, rock, sand and water. By adding fly ash or slag (byproducts from electric power plants) to concrete, the cement content can be reduced. ABI’s rock and sand are also locally produced.