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  • Writer's pictureAdam H. Cooke

What you need to know about Installing Solar Panels on your Home I

If you’ve been thinking about adding a solar power system to your home, you aren’t alone. Some 3 million systems sit atop American roofs, including about 400,000 that were installed each year in 2019 and 2020, according to Becca Jones-Albertus, director of the Solar Energy Technologies Office at the U.S. Energy Department.

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For many homeowners, the decision to go solar is a two-part process. The first is the financial side: Will the investment ultimately pay for itself and reduce or eliminate electric bills? Assuming the answer is yes, then you are ready to dive into the second — and more practical — part of the process: How do I get quality solar photovoltaic panels installed at my home by trustworthy professionals? Here are answers to some basic questions to get you started.


  • How does solar work?

  • Is my roof good for solar

  • My roof is kind of old. Does that matter?

  • Are all solar panels alike?

  • What is degradation?

  • Do panels work in all climates?

How does Solar Work?

Multiple panels are wired together into a solar array. When sunlight hits the panels, the energy is converted into usable electricity. Your home consumes the electricity produced by the system. The solar array connects to the local grid, so you receive electricity when panels aren’t producing enough or any electricity. The grid also stores any excess solar energy you produce and, through “net metering,” ensures you get credit for all of the electricity your system creates, whether you consume it immediately or send it to the grid and use it later. Energy efficiency helped the Empire State Building save money and cut carbon. It can help you, too.

Is my roof good for solar?

Adequate sunlight is key. Solar panels won’t work for rooftops heavily shaded by trees or adjacent structures, says Jason Gonos, co-owner of Power Production Management in Gainesville, Fla. Other roadblocks include insufficient roof space, a complex roof design, or the age and slope of your roof. Typically, solar panels perform best on south-facing roofs with a slope between 15 and 40 degrees. However, east- and west-facing roofs also work. A good starting point is the website of real estate company Zillow, Jones-Albertus says. Type in your address and look for the Sun Number score. The Sun Number ranks the suitability of a structure’s rooftop on a scale of one to 100. The higher the number, the better suited a home is for solar.

My roof is kind of old. Does that matter?

Yes. Your roof should be less than 10 years old or, if it’s a roof with a longer-lasting material, such as tile or slate, have at least 10 years of life left. It should also be in good to excellent condition. Why? “Because if you have to replace your roof for any reason other than insured storm damage, it is expensive to uninstall and then reinstall the panels and frames,” Gonos says. Are all solar panels alike?

Although panels operate similarly, the key difference is efficiency: how much sunlight they convert into energy. Typically, high-efficiency panels come with a higher price tag but produce more electricity over the life of the system. If you have a smaller roof, you may opt for more efficient panels. Those with a larger roof may also choose high-efficiency panels to use fewer of them overall, says Peter Faricy, chief executive of SunPower, a leading residential and commercial solar company based in San Jose. “Be sure to ask any potential installer if the suggested panels are the most efficient you can buy. Consumers should look for panels that are 20 percent efficient or more,” he says.

What is degradation?

Degradation is a measurement of how much efficiency is lost over time. Faricy says panels should retain 80 to 90 percent of their efficiency over 25 years. Do panels work in all climates?

You don’t have to live in famously sunny California or Arizona to go solar. In fact, one of the largest adopters of solar is Vermont, Jones-Albertus says. Of course, panels produce more energy on clear, sunny days in the spring, summer and fall, but even on winter’s shortest days or during rainstorms, the panels will generate some electricity. Although a snow-covered panel can’t generate electricity, snow doesn’t stick too long to the steep, slick panels.

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Are solar panels easily damaged?

They are built to withstand wind, hail, snow and torrential rain. According to Gonos, at minimum, a solar panel can take a pummeling by up to one-inch hailstones. Any weather event that will break panels will probably damage your roof first. “In fact, the biggest problem is not hail or storms. It’s squirrels that chew the wires,” says Ben Delman, spokesperson for Solar United Neighbors, a nonprofit that helps people go solar.

How do I find an installer?

Ask friends, neighbors and family who have gone solar about their experiences. Check review websites such as EnergySage, SolarReviews. When looking at reviews, make sure you are comparing your roof with ones of a similar material (slate, tile, shingle).

What am I looking for?

You want a company that has been in the business for a long time and is going to see the process through from beginning to end. Avoid those selling solar energy systems installed by a third party. These are intermediaries who hire contractors and bear no responsibility for installation quality or performance. “You want one that sweats the details,” Faricy says. For example, the installer should discreetly hide the conduit from the panels on the roof to the battery storage unit in the garage to maintain your home’s aesthetic qualities. Gonos is a proponent of local companies. “I like that I can walk into their office or showroom,” he says.

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Will I hear false claims?

Hopefully not, but be wary (or just walk away) when you hear these types of statements: “Your system will offset 100 percent of your electric bill.” “The government is going to pay for all of it.” “You’ll get paid to go solar.” “We don’t represent one particular company or product. We work to get the best product for you.”

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How long is the process?

Typically from the time you agree on terms to the installation is two to three months, Delman says. Installation takes one to three days, depending on the size of your home and whether you opt to add battery storage and/or an electric vehicle (EV) charger. After your panels are installed, there may be a post-installation inspection, then the utility company will connect you to the grid. What kind of warranties come with my system?

Your installation should come with three warranties: product, performance and labor. Product warranties cover potential defects in your equipment. Performance warranties guarantee that your panels won’t degrade by more than a certain percentage per year and will still produce a minimum percentage of their initial rated capacity for a set number of years. Both of these warranties should be for 25 to 30 years. A labor warranty covers the installer’s work, including electrical wiring and roof damage. These typically run three to 10 years. “In general,” Gonos says, “a well-known manufacturer that has been in business a long time will be able to honor a warranty.”

Any add-ons I should consider?

About 80 to 90 percent of our customers are asking about battery storage as a way to generate and save their own power,” he says. The right-size solar system will recharge your batteries every day. At sundown, the batteries then power your home, drawing less electricity from your power company. And should the utility grid go down, solar continues to work, so you can use your battery to power your basic home electrical needs, such as lights, refrigerator or designated outlets.

Do solar panels require much maintenance?

Not really. They don’t need to be washed; rain and snow will do the job. If you live in a dry and dusty area, an occasional professional cleaning may improve performance.

Where can I find more unbiased information?

Both Solar United Neighbors and the U.S. Energy Department offer helpful guides and fact sheets. SUN’s Go Solar Guide and the Energy Department’s Homeowner’s Guide to Going Solar offer an intro to what people should know as they start researching. The Solar Owner’s Manual offers in-depth information for prospective and current solar owners. For a deeper dive, read about solar panel basics and how solar works. SUN’s Battery Storage Guide is a comprehensive review of battery technology and economics.

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