Home heating systems that use solar or geothermal energy can trim rising energy bills, all thanks to Mother Nature. The sun and earth both offer clean and inexhaustible energy, and the means of harnessing their riches are expanding as consumer interest heats up. New homes offer a shining opportunity for the incorporation of solar and geothermal technologies, but your current home can achieve new levels of comfort with an earth-friendly, value-enhancing retrofit.
Here are the basics on how solar and geothermal systems work:
Solar Powered Solutions
How it works: Solar-powered home heating systems make the most of the sun's rays by linking solar collection methods with mechanical equipment that converts solar heat into usable, directable energy. There are two types of "active" solar systems: thermal and electrical.
With a thermal system, the transfer is made by circulating water, air or antifreeze to pumps and heat exchangers in order to power domestic hot water systems, heat pools, or warm up radiant flooring.
To use the sun to create electrical energy, photovoltaic cells, which convert the sun's energy into electricity, are mounted on the roof as solar panels or solar shingles, which can deliver electric power to your house without the need for bulky solar panels. Through a metering system, the electricity can either be used directly or fed back into the power grid and deliver a credit on your next electricity bill.
Besides active systems, sun-powered comfort in a home is further enhanced by such passive-solar design elements as advantageous orientation the landscape, overhangs and shading, smart and strategically placed windows, proper insulation, and construction materials with the thermal mass to effectively absorb and store solar energy during daylight hours.
Benefits: as log as there's a sun in the sky, you've got the opportunity for clean, quiet, natural power on the cheap. What's more, some local governments and utilities offer incentives for such systems, and if your solar power source is tied into the local utility's meter, they could be paying you for the excess when your system produces more than your home can use.
Drawbacks: When the clouds roll in, your solar collection rate goes down. For that reason, solar systems typically include connection to a conventional, backup power source.
The future: Present, solar systems are still a bit on the pricey side, but as interest grows and technologies improve, the sun's rays are becoming an affordable source of home comfort. The U.S. Department of Energy's Solar America Initiative is also scooting things along, with the goal of making solar energy completely cost-competitive with conventional forms of electricity by 2015. On the way, photovoltaic technologies could generate enough electric capacity to power 1.25 million homes and help us avoid seven million metric tons of CO2 emissions per year.
How it works: Geothermal systems go underground to draw out the earth's natural warmth for power and comfort. It's an approach that's been used for thousands of years in some parts of the world, and the United States is currently the world's leading producer of this type of energy. Utility-related plants can dip as much as a mile underground to collect the earth's proceeds, but on a purely residential level, the constant temperature in the top 10 feet of the earth's surface is the perfect zone for the refrigerant-filled piping needed to power a geothermal heat pump.
Benefits: Geothermal heat pumps are clean, quiet and far more efficient than standard air-sourced models, with Energy Star-qualified products using about 30 percent less energy by comparison.
Drawbacks: There's a lot of specialized planning and digging involved in a geothermal heat pump installation, and at present, system costs are significant. However, thanks to the major energy savings a heat pump provides, the investment payback period is reasonably brief.
The future: Just as with solar panel solutions, advancements in the development and availability of geothermal heating technologies are helping to lower system costs and increase opportunities to literally get grounded with a sustainable energy resource.