One of the hottest things about building a home is seeing new technology in action — especially when that includes using alternative energy to decrease your home’s energy burden without decreasing its beauty, functionality or suitability for your lifestyle.
“All the technologies for powering your house with alternative sources of energy are available on the shelf right now. You don’t have to invent anything or wait for anything to be invented,” says Jeff Demme, an alternative energies coordination expert based in Florida.
To make the most of alternative energy and be happy with your choice, articulate for yourself to what degree you are willing to change your behavior — for example, do you want the exact same level of convenience and control you have with traditional energy sources, or are you potentially willing to take some steps toward controlling use of electric appliances, lowering your thermostat, line-drying your laundry and foregoing air conditioning?
“In other words, what shade of green do you want to be?” says Chris Callahan of New York-based Callahan Engineering www.toolbase.org/TechInventory/ViewAll.aspx, coordinated by the PATH (Partnership for Advancing Technology in Housing) and the National Association of Home Builders (NAHB) Research Center.
Of the technologies making the most impact on the mainstream residential market, solar power and geothermal energy exchanges are among the most versatile with plenty of manufacturers willing to compete to make their products efficient and user-friendly.
“From an economic point of view, the success of a solar power system depends on your climate and your electric rates,” Demme says. “If it would cost a lot of money to bring electric to your house — if you’re going to spend tens of thousands of dollars to bring the electric lines into your property — I’d strongly recommend off-grid solar.”
An off-the-grid, whole-house system could cost $30,000 to $50,000, Demme says, but you might be paying close to that for an electrical hook-up, and you get the satisfaction of a lower energy footprint.
On a smaller scale, such as installing a few roof panels that can power the air conditioner for the few days a year that you need air conditioning in the mountains, or to take over the electrical power for some appliances, solar power can be very cost-effective. “You could have four hot tubs going, but not have a big energy footprint,” Demme says.
Of course, it’s not all sunshine in the world of solar power; there will be property issues to consider. First, check the local or association by-laws. If you have neighbors, they might not be impressed with a view of your solar array every time they look out their windows. Also, location may play a role: If you’re backed up against a mountain range that blocks direct sun through most of the morning and again in late afternoon, you may not be able to get the charge you want.
Another source for energy is geothermal, also called geoexchange. It involves installing pipes into the ground or groundwater to take advantage of stable below-the-surface temperatures. At a depth of six feet, for example, the ground in most climates is between 45-70 degrees. In winter, it’s much easier to capture heat from soil that’s already 50 degrees, than from outside air that’s below freezing. In summer, a geoexchange system sends excess heat from the home underground, and returns cooler ground-temperature air.
By using ground temperature as leverage, geoexchange systems don’t need to burn fossil fuels to create heat or air-conditioning. Fluid circulating in the pipes carries heat to an indoor component that uses compressors and heat exchanges to concentrate this energy and release it inside the home at a higher temperature. In summer, the process is reversed: excess heat is drawn from the home, expelled to the loop and absorbed by the ground or water.
According to the U.S. Environmental Protection Agency, geoexchange systems save homeowners 30-70 percent in heating costs and 20-50 percent in cooling costs compared to conventional systems. The indoor component is relatively small (it can fit easily in a closet) and is quiet. The pipes themselves can be installed horizontally at 3-6 feet below the surface for properties where trenches are easy to dig and space is not at a premium, or vertically (450-600 feet deep) for smaller lots or in order to minimize the impact on the surface of your property. The main drawback? If your property features a lot of rock ledge and installation would be expensive, and electricity is cheap in your region, geothermal may not be cost-effective. Also, geothermal systems aren’t stand-alones; they do require electricity to operate the pumps that draw heat in and out of your home, and to concentrate the energy drawn from the ground temperatures up to a level that provides a comfortable temperature for indoor living.
Plus, drilling costs may vary widely region to region. “The same geothermal system may cost $40,000-50,000 in New Hampshire, but less than $10,000 in Pennsylvania,” Demme says.
A third source is wind — though wind-powered generators for residential settings still feature some issues that are less prevalent with other forms of alternative energy. The biggest of these issues is the reliability of the wind itself.
“You have to have a strong wind location,” Demme says. “You need 12-15 mph average, every day, all year round.”
Installing a wind-powered generator in a less-gusty location can actually increase your use of traditional energy sources, Demme says. If the inverter that connects your turbine to an electrical grid requires 500 watts to run, and your turbine is only generating 300 watts, you’ve just gone into energy debt.
Of course, the biggest factor is that the home itself should be well-designed and well-built. Large overhangs will protect your house from excess heat gain in the summer, and good insulation in the roof, good thermal mass in walls and highly rated windows will maintain indoor heat in the winter.
“However you’re heating and cooling the house, building it correctly is the best way to decrease your home’s energy footprint,” Demme says. “A two-ton heat pump can heat the same house as a four-ton pump if the house is built properly. And it uses a lot less energy and costs a lost less.”
This article originally appeared in the May 2008 issue of Country’s Best Log Homes.