While the planetary benefits of using residential solar seem obvious, the benefits for the individual homeowner are somewhat less clear. The equipment that harvests the sun's energy can be rather costly, yet homeowners begin saving money on their utility bills from the day their solar systems are installed. Over time, those savings pay back the initial costs of the equipment, and continue to reduce energy expenses for many years. There are a variety of ways to determine what the payback time might be, and it depends greatly on where you live and which type of solar components you've selected.
The average U.S. home uses 11,280 kilowatt hours per year, and a 5 kw photovoltaic solar system may generate about half that total. It's difficult to forecast the electrical output exactly, but after installation, many modern PV systems are equipped with apps that report exactly how much electricity they're producing. To determine your actual savings, multiply the number of kilowatt hours your system is expected to generate annually by your current electrical rate. Divide the cost of your installed system by the annual savings figure to determine how long it will take for those savings to equal the cost of your installed equipment. Depending on how government subsidies in your area affect the equipment's initial costs, payback can range from four to 15 years.
Solar thermal components can supply as much as 90 percent of a home's hot water needs, but the hot water produced by such systems also can be used in boilers that provide radiant heat. The rooftop vacuum tube panels employed by these systems cost 60 to 75 percent less than photovoltaic panels, and offer much faster payback times. When government financial incentives are factored into the cost, payback for a solar thermal system ranges from five to 10 years. Another option, solar swimming-pool heaters, are a low-cost alternative to electric or natural gas-powered units.
The simplest solar technologies use the sun's energy to provide hot air for your home in the winter. Some residential solar heaters are scaled-down versions of commercial solar furnaces that can be used for whole-house heating, but solar convection systems are much more common. These inexpensive solar convection space heaters cost as little as one-half the cost of solar thermal, while silently pumping up to 10,000 Btu of heat per panel. A modestly skilled do-it-yourselfer easily can find online blueprints for creating her own solar convection heater using some two-by-fours, two four-by-eight-foot sheets of clear Plexiglas, and 240 empty beverage cans. The payback period for a DIY solar space heater may be as little as two months.
There are several factors that determine whether solar is a good choice for your home, starting with simple geography. For instance, the Pacific Northwest is considerably cloudier than the southwest, which may result in less availability of solar energy to harvest, thus, slower payback. Another factor that varies by region is government incentives. Some states and communities offer extensive rebates and tax subsidies to reduce the cost of buying and installing solar components, while other states are less generous. The U.S. Department of Energy offers an online database that reveals the current incentives for your specific locale.
Solar-equipped homes sell faster, and earn a higher sale price. For example, a 2011 study by the Lawrence Berkeley National Laboratory found that California homes equipped with photovoltaic systems sold for an average of $17,000 more than comparable homes without solar PV. The increased value often exceeds the actual purchase price of the equipment.
- Energy Center of Wisconsin: What's the Payback?
- U.S. Department of Energy: Database of State Incentives for Renewables and Efficiency
- U.S. Department of Energy: Solar Water Heaters
- National Renewable Energy Laboratory: Solar Heated Fresh Air Cuts Heating Costs
- New Energy And Fuel: The Best Thermal Solar Panel Might Be the Cheapest
- Treehugger: How to Build a DIY Solar Air Heater From Old Soda Cans
- Solar Power Rocks: Click Your State to See Available Solar Subsidies, Incentives, and Rebates
- U.S. Energy Information Administration: FAQs
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