Every home – new or existing – can increase its energy efficiency with the installation of a blanket of continuous exterior insulation over the walls and studs, thus reducing thermal bridging. This white paper identifies thermal bridging and why continuous insulation is the best way to address it.
While going off the grid entirely may be difficult for many homeowners, generating a portion of a home’s electrical needs is definitely doable. The payoff depends on the tax incentives from the U.S government, state governments and local utilities. The tax rebate picture is changing at the end of 2010, so make sure you have the latest information to help make a decision.
Also make sure you understand your utility company’s net-metering policies, which allow you to sell excess electricity to the power grid.
In any case, here are some methods by which you can generate electricity at a higher level of efficiency, and in two of the three examples here, without using fossil fuels.
As prices drop, residential solar power is on the rise, thanks in part to the available tax credits and rebates that make it more affordable. Residential solar power, which relies on photovoltaic panels, or PV for short, make sense as way to generate power close to the user while eliminating use of fossil fuels. The payback on the installation cost will vary depending on your incentives and utility rates.
EnerGen: Building products powerhouse Certainteed launched the Energen system that incorporates thin-film laminates with a traditional asphalt roofing shingle. The PV laminates lie flush with the roof providing a streamlined, visually appealing appearance. By making solar roof panels attractive, Certainteed hopes more people will adopt the solar power for their homes.
The system is designed to be installed by roofing contractors without requiring extensive training. The panels provide power in low and diffused light or even partial shade. Currently CertainTeed's Energen photovoltaic systems are available in California, Arizona and Hawaii only.
Wind is one of the greenest forms of energy, as it uses no fossil fuel and does not emit greenhouse gases. Most homes that have residential wind installation are still tied into the power grid, both to use electricity when the wind’s not blowing and to sell excess power to the grid when it is. A typical residential wind system can offset 1.2 tons of air pollutants and 200 tons of greenhouse gases.
New home wind options make it easier to install a wind turbine in a residential footprint, on the roof or on the ground on the home’s lot.
Honeywell Wind Turbine: The Honeywell turbine, marketed by WindTronics, gets rid of the inefficient gearbox found in traditional horizontal turbines, the kind found in utility-size wind farms. Instead, the electric generating mechanism is housed in the blade tips and frame. The blades generate electricity as they turn in the wind, as low as 2 mph. The unit weighs 170 pounds and measures 6 feet in diameter.
“It is our vision to bring distributed wind energy to life by making it a natural part of the power infrastructure,” said Reg Adams, president and CEO of WindTronics. “We’ve designed the Honeywell Wind Turbine to generate power where we live and work.”
The Honeywell Wind Turbine generates 2,752 kWh per year in a Class 4 wind speed at 33 feet. The system, including an inverter and controller, has an MSRP of $6,495.
Windspire: The Windspire vertical turbine offers a new spin on wind energy, as it’s designed for urban and suburban areas. The vertical design means the Windspire always faces the wind. Depending on wind speeds in a particular area, a homeowner may install two or three systems to generate 100 percent of the required power. One homeowner in Nevada installed a single Windspire to generate about 25 percent of his home’s power supply. Each Windspire will generate approximately 2,000 kWh a year based on 11 mph average annual wind speed.
To find the annual average wind speed for your area, click here.
Micro combined heat and power (CHP) systems generate both from a single fuel source, squeezing efficiency out of every last drop. They’re called “micro CHP” because the idea has been downsized enough to make sense for residential-level power generation, after years of use on a much larger scale by industries and utilities.
In a micro CHP a fuel source such as natural gas is used to generate electricity, and the excess heat from that operation is used to heat a home and in some cases water as well. The efficiency of converting fuel to useful energy may be as high as 90 percent.
freewatt plus: In August ECR International introduced freewatt plus, a microCHP system that produces heat and electricity and also provides backup power in case the home loses electrical service. The freewatt plus system combines an Energy Star-rated high-efficiency natural gas or propane furnace or a boiler with a Honda generator to generate heat, producing electric power as a byproduct. The electricity produced can be used to power the home or can be sold back to utilities. The backup system provides up to 1,800 watts to a home in case of a power failure, allowing up to six loads such as heating, a security system, a sump pump or refrigerator to continue to operate. A water heater option is available.
ClearEdge: A variation on the microCHP, the ClearEdge5 employs fuel-cell technology to generate electricity and heat. The ClearEdge5 converts natural gas into locally generated electricity and heat, while significantly reducing carbon dioxide (CO2) and energy costs. The fuel cell uses a proton exchange membrane to convert natural gas into hydrogen. Then an electrochemical converts the hydrogen to electricity. The natural gas does not burn, so there is a dramatic reduction in pollutants and greenhouse gases. The electricity flows through an inverter to power the home, and the excess feeds into the electrical grid. Heat produced in the cycle is transferred through a system for home and water heating.
Right now, the fuel cell system works best in larger homes, about 3,000 square feet and larger. It generates about 120 kWh a day and it’s especially efficient in a home with a pool, spa or radiant floor heating. Smaller units in development will be suitable for smaller homes.
Although locally distributed power generation may not replace utilities for years to come, homeowners can use it to better manage their energy costs and reduce their carbon footprint.
Gary Wollenhaupt /
Gary Wollenhaupt is an experienced writer and editor, with a background as a daily newspaper reporter as well as corporate and agency public relations and marketing. He is constantly looking for affordable green upgrades to make to his home in eastern Kentucky. www