In sizing up a prospective house, more and more homebuyers are asking themselves how the property rates on the green scale. While most houses weigh in on the low end, a subtle shift is underway as green building gains momentum among architects and developers. Eco-construction is fast evolving beyond low-flow toilets and energy-efficient appliances. From basement to attic, homebuyers can find a host of eco-friendly innovations that conserve energy, water and resources while maintaining the health of inhabitants.
The first priority in evaluating a home is positioning. Construction on an east-west axis for homes in temperate or cold climates helps make the most of solar heat during the winter. East and south windows can reap 57 percent of a home's heating requirements through passive solar heating. In southern climates, windows and porches are best placed to capture prevailing summer breezes while overhangs shade the interior. Exterior paint colors are important as well, with light shades best suited for temperate and warm climates, where they work to reflect the sun's heat and reduce cooling costs.
Today's homes are 35 percent more energy efficient than those built 20 years ago. One factor is the Environmental Protection Agency (EPA) Energy Star appliance program; another is newly available technology. In green homes, high-tech means solar photovoltaic cells, heat exchange ventilation systems, geothermal heat pumps, attic ventilation systems and radiant heating powered by floor-based cables.
“The baseline in all our green building work begins with energy efficiency,” says Bion D. Howard, a building environmental scientist in Upper Marlboro, Maryland. Some favorites on Howard's list of energy savers are furnaces equipped with clock thermostats, tubular skylights for places such as closets or dark hallways that would otherwise be lit with incandescent bulbs and kitchen floor pedal systems to control hot and cold water flow and lower heating costs. The pedals alone can save as much as 20 to 30 gallons of water per dishwashing.
Savvy homebuyers also look for heat preservers such as double and even triple-glazed windows, which help reduce the estimated 20 percent of energy typically lost through window panes. And utility companies may have something to contribute. Great River Energy in Elk River, Minnesota, offers off-peak and cycling programs that supply power to selected home appliances in 15-minute increments.
The homebuyer's checklist should identify potentially toxic building materials, such as particle board or cabinetry made with formaldehyde glues and preservatives. Safer alternatives exist, though the materials may seem bizarre.
For instance, builders insulated a renovated St. Louis, Missouri home with 3,000 recycled newspapers treated with nontoxic flame retardant. Innovative manufacturers have turned used soda bottles into carpeting, garden hoses into roofing material and agricultural wheat straw waste into a particle board replacement called agriboard.
The Energy Audit
Evaluating a new home may require some outside help. Formal testing can be arranged through local power companies, which will conduct energy audits. Radon testing is another good idea. Other problems to watch out for include: leaky roofs, insufficient grading too close to damp soil, and signs of mold and mildew indicating water seepage and a threat to air quality and materials preservation. For houses with crawl spaces, look for passive ventilation measures like vapor retarders combined with piping to direct radon gases away from the home. These systems also keep things drier.
Basements deserve special attention. “Seventy percent of a basement's moisture ends up in the rest of your house,” says Paul Frisette, director of the building materials technology and management program at the University of Massachusetts, Amherst. Moisture can raise allergen concentrations indoors, reduce the life of materials and necessitate more frequent paint jobs. Point source ventilation lessens the impact, and houses should have them over stoves, in bathrooms, anywhere moisture is generated.
In managing the water a house does want, eco-friendly homes will have a combination of low-flow shower heads, low-flow—or even no-flow—composting toilets, high-efficiency washers, rainwater catchments, and greywater systems for reusing household water in the lawn or garden. One ambitious approach surrounds a Calgary, Canada home with a modest wetlands system. A water line directs the house's wastewater from a settling tank to a plastic-lined gravel bed. Surrounding marsh plants then help process the water before drainage to a subsurface drain field.
Green builders may debate the finer points of home construction, but the bottom line is that no one approach will produce an environmentally benign home. Each decision means weighing how materials are made, how far they must be shipped and their degree of recyclability and durability. Although many consumers fret over high costs, builders report that prices are coming down for some technologies. Homes that meet the EPA's Energy Star standards cost just one to two percent more than power guzzlers. And what costs more up-front often saves money in the long run.