The size of your system. You can determine how much electricity you want to produce then size your system accordingly. Note that you can start out small and add on. A system that will generate 100 percent of your energy needs is expensive, so most systems are sized to generate only a portion of your home’s needs.
Your site. If you have a shade-free area from 9 a.m. to 3 p.m., you’ll be able to collect more sun and produce more energy than if your site is shaded.
Your region. The more sunny days in your area, the more electricity you’ll be able to generate. You can find online calculators to help answer this question in more detail, and installers can provide details about your situation, too.
A system that will generate 100% of your energy needs can be quite expensive. You can always start out small and add on, but most systems are sized to generate only a portion of your home's needs.
Battery-backed or grid-independent systems use on-site energy storage to store excess energy produced during the day for use at night or when the sun is not producing enough power. Choosing this option will add significant cost and maintenance to your system, but the technology is improving and the costs are beginning to decrease.
Most people opt for grid-connected systems for reduced cost, maintenance, and high reliability. With this type of system, your cooperative continues to provide energy to you when you need it 24-7. Your PV system will produce energy, and even excess energy, on sunny days. Your system will not collect sunlight at night and on cloudy days. That means you will continue to draw electricity from your cooperative during these times.
Most grid-connected PV systems shut down to prevent back-feeding electricity into de-energized power lines that may have fallen or that line crew members may be working on. It’s important to have this shut-down feature to prevent injuries—and even death—to those working on the line. PV will not be producing energy in this case.
The payback period can range from fewer than 10 years to more than 20 years, depending on the system cost, available rebates and incentives, the amount of electricity produced, and the retail price of electricity.
The price of PV components varies depending on the size of the system (generating capacity), the type and quality of the components purchased, and the complexity of the system selected. The good news for consumers is that the cost of PV has declined dramatically, while the technology continues to improve, allowing for more energy production from a smaller panel.
Installation costs depend on the size and complexity of the system, but also on the home layout and construction. For example, a simple, south-facing roof allows for an easier install than a roof with hips and valleys. In addition, some homes require structural or wiring upgrades.
An average 4 kW system may cost between $10,000 and $20,000, before credits and incentives. This is based on a typical installed cost of $2.49 to $5 per Watt of distributed generation capacity. To determine your costs, look for online calculators to help you estimate your pricing, and also get bids from reputable installers.
Certified solar energy products and systems generally are reliable, with a life expectancy of about 30 years. Manufacturers test solar panels for hail impact, high wind, and freeze-thaw cycles to represent real-life situations. Most manufacturers offer 20- to 25-year warranties for panels; extended warranties may be available at an extra cost.
Little maintenance is required; occasionally it may be necessary to rinse modules off with water to remove dust and grime. Other components like inverters may have a shorter life. Solar panels may outlast the roof where they are attached. Make sure your roof is in good shape or budget for replacement during the life of the system.
As this technology grows in popularity, so does the potential for deceptive or fraudulent sales tactics. A solar photovoltaic (PV) installation is a big investment, and you want to make sure you select a reputable solar contractor with licensed installers.
