- A solar-powered home is a house designed to passively capture the sun's heat through windows to warm the house. Or it is a house that uses collectors on the roof to heat water for home use and to heat the building. Or, it is a house with solar panels on the roof to generate electricity for the home to use. Often, a solar-powered home features a combination of these three main systems.
Passive Solar Design
- All houses soak up solar thermal energy to some degree. The sun comes through windows and warms the walls and floors. Passive solar design aims at optimizing the solar gain through strategic placement of windows, and massive interior or exterior walls (called thermal mass) to store the collected heat during the day and slowly release it at night. The angle of windows, the venting systems, the orientation of the house overall and the landscaping are all carefully orchestrated to get the most out of the sunshine available. These designs can work at any latitude, and in any climate. Of course, the particular design will vary greatly in different places. You don't want as much sun entering in southern Arizona as you do in northern Minnesota.
Solar Water Heating
- A Homemade Flat Plate Collector
Letting the sun heat your water can be as simple as filling a black plastic trash bag or an old inner tube with water, waiting a few hours, and running the heated water through a shower hose or into a tub. Home solar heating systems elaborate on this basic method. One design puts flat plate collectors on the roof. These rectangular, glass-covered boxes have black tubes of water running through them. The water soaks up heat and goes directly into your home's water system when needed. Another design uses a batch collector: a black, insulated tank full of water that heats up water in "batches," which is then pumped into your home water system. Hot water from both of these designs can also be used to heat your home, through radiant-floor or forced-air systems.
- A Typical Solar Panel
Photovoltaic systems use solar panels mounted on the roof to charge a bank of batteries. The batteries' DC power is run through an inverter to become standard household AC current, and the inverter sends the power to your regular wall outlets. Off-the-grid homes may need to supplement this system with a generator to supply electricity when solar gain isn't available. On the other hand, if you generate more power than you need with your solar panels, you may be able to make arrangements to sell it back to the power company.