Solar panels are becoming more common on roofs across the nation. They can save you money and reduce emissions, using an abundant source of power. But there’s a lot that might surprise you about solar panels. Read on for 21 facts you should know about this remarkable technology.
1. Solar panel technology is over 100 years old
Although humans have been trying to harness the sun’s energy since the 7th century B.C., the first solar cells were installed in 1883. Modern solar cells, like the ones we use today, were developed at Bell Labs in 1954. Since then, technological advances have made solar panels more efficient and reliable.
2. Solar energy is free, but solar panels are not free
3. Solar panels can save you money
Although solar panels aren’t free, they can still bring significant savings on electric bills. Also, many states provide homeowners with incentives to install solar, and the federal government offers a solar tax credit of up to 30% of the cost of installing a residential solar system.
4. The cost of solar panels keeps going down
The cost of installing solar panels has dropped by nearly $15,000 since 2010, according to the Solar Energy Industries Association. According to EnergySage, the average cost of installing a home solar system in 2025 is about $30,000 before federal tax credits and incentives, with the cost potentially dropping to $21,000 or less after federal and local incentives.
5. Solar panels take years to pay for themselves
The average payback period (the point at which the money you’ve saved by having the solar system exceeds the cost of the solar system) for residential solar ranges from 3.6 to 19.1 years, with an average of 7.5 years, according to EnergySage. The exact payback time depends on factors like where you live, the size of your system and how you pay for it.
6. Solar panels last a long time
Solar panels generally last 20 to 30 years with proper care and maintenance. Warranties for solar power production are typically 25 years long. Solar panels typically won’t stop working after these periods — they just get less efficient.
7. The efficiency of solar panels decreases over time
Solar panel efficiency is a measure of how well a solar panel converts sunlight into electricity. Although solar panels last a long time, they gradually lose efficiency as part of normal wear and tear — at an estimated rate of about 0.5% each year, according to the U.S. National Renewable Energy Laboratory. After 20 years, you can expect your solar panels to function at about 90% capacity.
8. Some solar panels are more efficient than others
Today’s residential solar panels are 21% efficient on average; some are up to 23% efficient. This means they convert 21% to 23% of the sunlight that hits them into electricity. More efficient panels cost more, but because they generate more electricity, they may save you more over the life of your solar system.
9. Solar panels are usually connected to the power grid
Unless you go completely off the electric grid, your solar panels will likely be connected to the grid. That’s because when your panels aren’t producing as much electricity as you’re using (such as when it’s dark outside), you have to draw electricity from the grid. When your panels are producing more power than you need, you can send that power back to the grid or store it in a battery for use later. In many states, you can get a credit on your electric bill for the power you send back (this is often called net metering).
10. In most cases, solar panels do not produce energy during blackouts
Because solar panels are connected to the grid, solar panels usually shut down when there’s a grid outage. That’s to protect utility workers from surges of power coming back onto the grid. To obtain electricity from your solar panels during a blackout, you can pair your solar panels with a solar battery.
11. Solar panels can produce energy on cloudy days
12. Solar panels require maintenance
Pollutants and particles that build up on solar panels can cause energy loss; in drier, dustier parts of the U.S. that loss can be as high as 7% annually. So it’s a good idea to clean your solar panels once or twice a year in addition to other solar panel maintenance work.
13. Solar panels can increase a home’s value and help it sell faster
According to a 2019 survey by Zillow, solar can increase a home’s value by up to 4.1%, depending on your location. In a 2022 survey, Rocket Homes found that homes with solar are more likely to sell over the asking price and also tend to sell faster, spending 13.3% less time on the market than homes without solar.
14. Solar panels can protect a roof
Solar panels can protect your roof from rain, hail and sun, potentially extending the life of your roof. Be sure your roof is in good condition so it can support the weight of the panels; a quality installer should do a site visit to assess the condition of your roof.
15. Some roofs are better for solar panels than others
Solar panels can be installed on many types of roofs, but the best types are asphalt, metal, tile, tar and gravel. If you live in the northern hemisphere, a south-facing roof is ideal.
16. Solar panels produce the most energy at specific roof angles
According to the U.S. Department of Energy, the ideal angle for solar panels on most U.S. homes is between 15 and 40 degrees.
17. Solar panels work better in cooler weather
Although solar panels generate more energy when they get more sun, they also generate more energy when they’re a bit cooler. The ideal temperature for solar panels is up to 77 degrees Fahrenheit; they work if it’s hotter than that, but they won’t be quite as efficient.
18. Solar panels can save more money if combined with heat pumps and electric vehicles
More than half of a typical household’s annual energy consumption is for space heating and air conditioning, according to the U.S. Energy Information Administration. Pairing solar panels with an electric heat pump, which is much more efficient than traditional furnaces, may significantly lower your power bills. Similarly, pairing solar with an EV may save consumers hundreds of dollars per year.
19. Solar panels create cleaner energy
All manufacturing creates some emissions. But once solar panels are on your roof, the energy they generate is clean and renewable. According to Columbia University, solar panels even reduce CO2 emissions more than trees.
20. Solar panels can be recycled
According to the Department of Energy, over 85% of the materials in a solar panel, such as aluminum and glass, are recyclable.
21. More solar panels are being manufactured in the U.S.
Most solar panels are still manufactured overseas, but the Inflation Reduction Act of 2022 is encouraging growth in U.S. solar manufacturing. According to research firm Wood Mackenzie, domestic solar panel manufacturing capacity has nearly quintupled since Q2 of 2022. EnergySage maintains a list of the top American-made panels.
Can I get financing for a solar panel system?
In addition to tax incentives and rebates, there are options available. Many solar installers offer financing, but you may also be able to finance your solar investment through a home equity loan or home equity line of credit (HELOC). These options may have lower interest rates than financing with an installer, future opportunities for refinancing and possible tax benefits.
Home equity loans and HELOCs are ways to borrow against the value of your home, converting equity into cash. With a home equity loan, you receive a lump-sum payment and then pay it back at a fixed interest rate over an agreed period of time, typically from five to 30 years. HELOCs are more akin to a credit card, something you use as needed. You’ll usually have 10 years to draw from the line of credit, during which time you only have to pay interest, and after that you pay both the principal and interest. HELOC interest rates typically are variable, meaning your monthly payment could rise or fall over time. And with each of these options, you’re using your home as collateral.
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Another option is a solar loan. Many banks, credit unions and online lenders offer these to fund solar panels and installation, with amounts typically from $1,000 to $100,000, and annual percentage rates ranging from 6% to 36%. They function like a personal loan: you receive a lump sum and repay it in equal monthly installments over a set period, typically two to seven years. And unlike with home equity financing, there is no collateral required for a solar loan. This means your home or solar panels aren’t at risk if you miss payments, but you may have to pay late fees.
So, yes, you likely can get financing. If you go this route, compare interest rates, terms and fees with any financing package that a solar provider may offer you to ensure you get the best deal.
