Details: The Solar Energy Tech Set
The most cost effective house will take advantage of both passive and active solar energy to lower or eliminate utility bills.
Passive solar design uses architectural features, not special equipment, to minimize mechanical heating, cooling, and lighting needs. Examples include using south-facing windows to allow sunlight to enter the home, masonry or other materials to absorb thermal energy, overhangs to shade windows, and windows, tubular skylights, or skylights placed strategically for natural lighting and cooling with prevailing breezes. Although passive solar designs do not require high-tech gadgetry, they do require a designer who is knowledgeable about solar geometry and building material selection.
View the Lighting Tech Set for additional passive solar design strategies by using natural lighting.
Solar water heaters come in a variety of configurations. A solar water heating system usually consists of a hot water storage tank, a solar collector that absorbs solar energy (often mounted flush to the roof), and (for forced circulation systems) a pump and controls. Most systems have back-up water heating such as an electricity or gas tankless water heater. Solar water heaters can heat up to 100 gallons of hot water a day. A Federal Tax Credit offers to pay 30% of the installed cost up to $2,000 through 2007.
Solar electric or photovoltaic (PV) systems convert solar energy directly into direct current (dc) electricity. An inverter converts the PV-produced direct current to common household current (ac). When a PV system is connected to the utility via the electric meter, the PV system can send power back to the utility grid when it is not needed in the home-which may reverse the direction of the meter. PV systems usually cost between $8,000 to $10,000 per kW, less the numerous federal and local rebates. An average 2 kW system will provide roughly half of a home's electric demand.
Photovoltaic cells can now be built into roof shingles. Different types of photovoltaic panels and their attributes are explained in DOE's publication, PV Systems.
PV systems typically require specialty installers who can design and install the various components of the system.
A vast variety of solar garden, spot and safety lights are commercially available. Using PV cells integrated into the light casing, solar lighting can be placed nearly anywhere without the restrictions of wiring.
Content updated on 4/8/2006