How Much Solar Power Is Needed for My Home?

A residential photovoltaic system can power a home throughout the year.

Small-scale solar photovoltaic systems allow homeowners to provide enough electricity for residential needs year-round. The size of a solar electric system depends on how much electricity a household uses, and the amount of power the system generates depends on the weather.

Requirements

According to the National Renewable Energy Laboratory, a photovoltaic system capable of producing between 1 and 5 kilowatts is needed to provide enough electricity for a typical home. A 2 kW system will likely meet the energy needs of an energy-efficient home, while a 5 kW system will meet the needs of a conventional home.

Consumption

According to the U.S. Energy Information Administration, as of 2008 the average U.S. household consumed 11,040 kilowatt hours of electricity annually. Systems using the most electricity are home and water heating, 18 percent; air conditioning, 16 percent; and lighting, 15 percent. Appliances like clothes dryers, refrigerators, freezers, dishwashers, computers and color televisions together consume approximately 28 percent of residential electricity.

Sunshine

When sizing a solar power array, a homeowner must take into account the amount of electricity consumed and the amount of sunshine available. In Arizona, which receives six hours of peak sunshine daily, a solar panel that produces 40 watts of electricity yields 240 watt hours. By contrast, Wisconsin averages 2.5 hours of sun daily in the winter; however, the solar effect is increased on clear days by light reflecting off snow.

References

• National Renewable Energy Laboratory: Get Your Power From the Sun
• Arizona Solar Center: Sizing a Photovoltaic System
• Richmond Times Dispatch: Home solar electric systems grow popular
• Wisconsin Solar Use Network: Solar Energy in Wisconsin
• U.S. Energy Information Administratioin: Frequently Asked Questions - Electricity