What You Should Know About Solar Panels

 1. Roof and house orientation. How much surface solar modules cover on a roof or how big the installation is on the ground makes a difference in the amount of energy produced. Generally, they are placed facing south or west to be exposed to the most sunlight, optimizing power, says Dickinson. Pearl Homes’ will cover 88% to 92% of a roof surface. Covering 100% may produce more power than occupants can use.

2. Panels. In recent years, panels have become more efficient, thinner, and better looking, thanks to monocrystalline designs that use a single photovoltaic cell rather than several cells that the older polycrystalline designs relied on. As a result, the updated panels can occupy less roof space because they pack in more power, O’Connor says.    

The number of panels installed is generally based on the amount of electricity occupants use, which is why an installer often asks for 12 months of electric bills, says Mike Koehler, vice president and solar business developer for Gardner Capital, St. Louis. If the next owner of a solar powered house uses more electricity, they might request a larger array, he says.

What this means for a homeowner who chooses a newer 400W panel, for example, versus older 370W panel, is that they may only need to install 38 panels instead of 41 and save about 33 square feet of roof space, Koehler says. And because the 400W panel is more efficient, it will generate more electricity, he says.

Installers also need to know local ordinances. For example, Evanston, Ill., doesn’t allow panels to stick up past a roof’s ridge line or be visible from the street if the roof is flat, says Kipnis. They also need to know local utility rules since some will buy back excess power, Koehler says. Rocky Mountain Power, which services most Utah customers, gives credit for excess energy, says Scott Cramer, president of Go Solar Group.  

3. Batteries. Extra energy can be stored in batteries. Different solar panel manufacturers prefer different battery companies. For example, Solaria buys batteries from Sonnen, Sharma says.

4. Installers. Installation costs have dropped as more installers have entered the niche and become more experienced, says O’Connor. Besides the modules and batteries, homeowners who go solar need an inverter to hold panels, wiring in place, and a meter. Sharma suggests homeowners ask installers which modules they use, the price of each panel, number needed, what they look like, how much shipping to the site will be, and if permits are needed.

5. Costs and return on investment. A typical panel system might run between $15,000 and $25,000, which includes ancillary equipment and labor, Koehler says. Yearly savings vary greatly depending on the utility and if it offers incentives, he says. The good news is that a typical warranty lasts a long time; Solaria’s is 25 years, Sharma says.

How much money is saved also depends on how a purchase is made. “If someone pays out of pocket, it may take seven to 10 years for a payback, but if someone leases the system, the savings will be less per month, but the homeowner has no upfront investment,” Koehler says. 

One caveat relates to whether a solar system will increase a home’s value. One study from the U.S. Department of Energy’s Lawrence Berkeley National Laboratory found that the panels are viewed as upgrades and home buyers have been willing to pay a premium of about $15,000 for an average-sized solar system. Additionally, the homes sell faster than those without solar.