systems

ERIE COUNTY, Ohio – A family farming operation in Erie County is working to reduce its carbon footprint. A local farm chef’s garden has received $2.5 million from the state to support its energy-sufficient projects.

Governor Mike DeWine and the Ohio Department of Development announced grants to six organizations in Cuyahoga, Erie, Franklin and Hamilton counties. The grants will be used for energy efficiency projects designed to reduce costs, improve the environment and improve the lives of people in Ohio communities.

“Each of these organizations plays a critical role in their communities, and these grants ensure they have the resources they need to continue their important work,” said Development Department Director Lidiya Mihalik. “By reducing energy costs, we provide the financial breathing room they need to innovate and enhance the vital services they provide to residents,” said Lidiya Mihalik, director of development.

Farmer Bob Jones and his family have been growing vegetables in Erie County for over 40 years. The farm grows 600 varieties of vegetables and ships them to restaurants and home consumers in all 50 states.

“This grant will allow us to expand our sustainable agriculture programs on the farm,” Jones said.

The money will be used to upgrade lighting and install a solar photovoltaic system.

“We capture solar energy from the sun and through photosynthesis we put that energy into the soil for the next crop. This soil here is going to be fall spinach, but we’re building energy in the soil,” Jones said.

According to Ohio State University, as energy prices rise, these costs take up a larger share of farm budgets. Many businesses are now considering new ways to manage energy use.

Jones said this project will allow them to generate 70% of their electricity needs on the farm.

“At a conservative estimate, that would save us 50% of our total electricity costs in a given year. It just gives us money to spend on other projects and its workers in processing or factories,” he said.

To help keep the farm viable and profitable for future generations.

“The concept behind it is really a paradigm shift in realizing that we didn’t inherit this land from our grandparents. We’re borrowing it from our grandchildren, and we have to leave it in a better condition than we found it,” Jones said.

Storage tank failure has plagued the oil and gas industry for a long time. However, fluids there are not kept at high temperatures by daily heating and cooling cycles, as is the storage of concentrated solar thermal energy.

One of the failure mechanisms in the steel used in the thermal energy storage tanks of the CST and CSP plants has been isolated, and a steel formulation from Finnish stainless steel firm Outokumpo has now been successfully tested by the Colorado School of Mines.

Today’s commercial CSP technology depends on storing the thermal energy of an extremely high-temperature fluid in a giant open tank. These tanks can hold thousands of tons of molten salt, an extremely hot liquid at high pressure that varies between 300°C and 600°C every morning and evening as it is heated daily and cooled.

The industry standard metal for these tanks has been grade 347H austenitic stainless steel. However, failures in some high-profile storage tanks have been attributed in part to this choice of steel.

How the steel and weld behaves under the heat cycles as it goes through the welding process is where it fails. The welding process changes metallurgy. Under a certain stress and temperature, some alloy components migrate to the grain boundaries, causing the material to become brittle and crack at the boundaries. This phenomenon is known as Stress Relaxation cracking.

“Diagnosing stress relief cracking in real project storage tank failures is extremely difficult,” said Kurt Drewes, technical director at Australian solar firm Vast Energy.

Although it is impossible to conduct failure tests in giant tanks containing molten salts, the Colorado School of Mines conducted laboratory tests on this 347H steel to understand the causes. They showed that welds fail due to stress relaxation cracking (SRC) in the steel.

Post-weld heat treatment (PWHT) can reduce some of this tendency, but is almost impossible to achieve on the scale of a typical storage tank built by industry.

Alternative stainless steel formulation; Therma 4910

When the entire industry experience is built around one material, it’s very hard to say that you need to go back and find a more robust alternative. But now Vast, Outokumpu and the Colorado School of Mines have found and demonstrated an alternative. Stronger steel for tanks.

An old formula from the Finnish high-temperature stainless steel company Outokumpu has now been successful in preventing heat storage tank failure in weld joints.

“The logical answer is to try and find a material that you don’t need to PWHT to achieve structural integrity. And tests of this new steel formulation have shown it; that it’s possible,” Drewes said.

Led by the Colorado School of Mines, Vast tested the Therma 4910, now known as the 316 LNB. It is an alternative steel formulation supplied by the Finnish company Outokumpo, one of the world’s largest stainless steel producers.

“Of course, some other steels are not prone to stress relaxation cracking, but they have lower creep and fatigue strength. 316LNB has similar or better creep fatigue properties than 347H and is less prone to stress-relief cracking,” added Bruce Leslie, head of product development at Vast.

This alternative steel formulation is slightly more expensive than the traditional one. However, Vast is sounding the alarm that a thermal storage tank failure will cost the entire industry its reputation for reliability. Therefore, they feel an urgency to inform the industry about a new option in material selection.

The dirty industry of the 1980s is driving the clean industry of the 21st century

“This formula is not really a newly developed new material,” Leslie noted.

“It was developed for coal-fired power plants in the 80s and 90s. There was a big push to move to very high temperatures and pressures in coal-fired plants. So 316LNB was used quite a lot, but then cheaper stainless steels were made that worked for industrial needs. But there is a lot of test data and information about it. So, this is a tried-and-tested material.”

The transition to this “new old” storage tank material has become even more urgent today, given that a new solar sector generating heat for industrial processes and solar fuels is just starting up: CSP may be required to generate only solar energy. Up to 600°C, these new processes should guarantee continuous heat production around the clock and at higher temperatures up to 1500°C.

It is now being tested at the Colorado School of Mines

The Colorado School of Mines now performed the same tests they did on the old steel formula, the new 316LNB steel.

“We were aware of the previous tests and thought it appropriate to repeat the same tests on the new material,” Drewes said.

“It’s a structural test of the structural failure of materials and what happens during welding. We simulate the effect of welding on materials in those tests. What they show is that the 316LNB has solved these issues. It has low levels of carbon and increased nitrogen and boron, which give it these properties. And we argue that it is the more preferred material for the CSP industry.

Testing has shown that this formulation is resistant to this failure mechanism. They will present their results at the SolarPACES Conference in Rome later this year. Vast and Outokumpo co-funded the trials with Vast, along with construction partners CyD.

Drewes noted that Vast is interested in having reliable thermal storage tanks and that Outokumpo, which offers special materials for this application, is interested in promoting the use of its high-temperature steel capabilities. He said that they can meet these requirements and believe that thermal energy storage will be the future as a necessary component of the New Energy Transition.

In previous work, Vast focused on strengthening the floor of these giant tanks to prevent buckling, which is just one aspect of improving the stability of thermal storage tanks. The firm is working on other tank improvements for its projects with the DOE, but Drewes and Leslie see the solution as important information for the industry as a whole.

Fix for tank leak blocking Vast Solar’s first Tower CSP

Broad Solar Consortium Patents Flexitank; Prevents thermal storage leakage

JACKSON, Miss. (WLBT) – WLBT told you last week about Hinds County Supervisors approving the state’s largest solar panel project.

It’s called the Solar City Project.

It’s a decision many Hinds County residents aren’t happy with.

More than a thousand of them signed a petition against the project.

Now, one resident is taking things a step further by filing an appeal against the decision.

“There are many, if any, but we try to prevent them,” said Allison Lauderdale, who filed the appeal. “We’re trying to prevent damage.”

On Friday, Lauderdale stood with dozens of others opposing the county’s decision to bring the project.

“No one stood up to the people who opposed it,” Lauderdale said. “It seems quite clear that their interest is more in the company than in being the voice of the people.”

Lauderdale appealed on several grounds, including that the project violated zoning ordinances and constitutional rights.

“They’ve had three or four years to prepare for this and they’re giving us three minutes to speak at meetings,” said the Raymond resident. “It’s very disappointing and says a lot about our elected officials.”

The county is partnering with Apex Clean Energy. The project is expected to generate up to $150 million in tax revenue, as well as provide more than 400 construction and farm jobs.

Hinds County leaders say it will be a 65-hundred-acre solar panel farm that could generate enough energy to power more than 95,000 homes across the county.

However, Lauderdale said he is still against it.

“We want people not to see any houses here,” Lauderdale said. “They’re going to sell it to a private entity like Facebook or Amazon, and we’re not going to get any benefit from it, but we’re still left with the mess and the consequences.”

Lauderdale says they plan to continue speaking out against the project. If approved, Apex plans to begin construction late next year.

Hinds County board President Robert Graham said he had no comment at this time.

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See a spelling or grammar mistake in our story? To report please click here and include the title of the story in your email.

Copyright 2024 WLBT. All rights reserved.

Pineville, La. (KALB) – William Albritton of Pineville went from being an engineer at Pan Am to starting his own solar company.

His company, Strata Energy, is based in Pineville. Formerly known for founding the Iron Boot Gym, William now focuses on bringing solar power to businesses.

Strata Energy aims to help businesses save money and protect the environment by offering clean energy solutions. His deep roots in Pineville make his mission even more credible.

“I remember growing up in Indian Hills in Pineville, riding bikes and dreaming up all kinds of wild ideas like boys often do — inventing things and all that. Now, starting Strata Energy, I feel like a kid again, starting to make those dreams come true where I grew up,” said Albritton.

Click here to learn more about Strata Energy.

Click here to report a typo. Please include the title of the article in your email.

Copyright 2024 KALB. All rights reserved.

See at NRG

NRG Clean Power

Best in California and Texas

See at Renu

Renu Energy Solutions

Great option for the Carolinas

Show more (3 items)

The companies providing quotes may differ from those described in our independent reviews.

Why Palmetto Solar is CNET’s best overall solar company

Palmetto Solar earned the top spot on CNET’s best solar company list in large part due to exemplary customer service and a suite of quality solar panels and solar battery offerings. Our staff of editors and writers has reviewed and evaluated 17 solar companies so far. While it’s true that many of these companies offer quality equipment and good customer service, Palmetto stood out because of its price transparency and robust customer service plans. In an industry that can be hard to navigate, Palmetto’s transparency is a valuable metric to consider. 

Palmetto operates in 26 states, including many of the most populous ones, making the company accessible to most of the US. But if Palmetto isn’t available to you or doesn’t offer you the best deal, we’ve scored other solar installers highly too — including some installers that work in all 50 states. You can find the whole host of solar companies reviewed by CNET experts below.

The best solar companies of 2024

This best list draws from national or otherwise notable installers of (mostly) rooftop solar panels. Some of our picks might provide commercial installation services, but every company we’ve chosen for this list has been selected based on their service regarding residential installations. Our selections might change as we review more companies or as companies change their offerings. CNET experts have written or edited each of the reviews this best list draws from, and developed a special in-house scoring methodology. Throughout this process, our writers have spent hours reading equipment spec sheets, looking at national trends, investigating customer reviews, interviewing industry experts and speaking with representatives from many of these companies to rank them on the criteria that matters to you.

These companies were rated on the variety and quality of equipment and products they offered, their stated warranties and apparent commitments to customer service. (Customer service is difficult to pin down and therefore makes up a smaller portion of a company’s total score, even though we recognize that it’s a significant part of the purchasing process.)

Besides our top pick, Palmetto, several other companies ranked above the competition. They all offer solid equipment but stand out in specific ways: SunPower, for premium solar panels; Tesla, for lower prices; and Momentum, for its in-house installers. NRG Clean Power and Renu Energy Solutions stood out as exceptional installers in more localized regions as well.

Palmetto Solar

Best overall

Solar panels are typically low maintenance equipment, but they’re also unfamiliar. If you want to reap the benefits of solar but will have a bit more peace of mind if someone else is making sure it’s working, Palmetto might be a good fit for you. Just remember to add the cost of Palmetto’s monitoring service in to your payback period calculations.

SunPower Solar

Best solar panels

If you’re looking for top-of-the-line solar panels, SunPower is your best choice. But don’t write it off if you’re looking for a less flashy installation that will get the job done. This year it started installing Qcells panels, which should make an installation from the longest-tenured company on our list available to more people.

Elevation

Whole home approach

Elevation’s focus on your home’s energy efficiency isn’t the norm in the industry. If you’re planning on addressing energy efficiency first, working with Elevation allows you to keep the whole process with one company. Elevation’s solar equipment comes from well-established and well-regarded companies. Elevation’s warranties on workmanship and weatherization could be a bit longer.

Freedom Forever

Best for cash customers

Include Freedom Forever in your search if you want the backing of a national company that installs a wide variety of the most popular solar equipment available. Freedom Forever also extends a couple of products that take some of the pain and risk out of going solar, like a production guarantee and an escrow option with cash purchases. Online reviews say customer satisfaction has been low of late, though the company says that’s changing.

Tesla Solar

Most affordable

Tesla’s solar branch seems to be the least loved of Elon Musk’s ventures. Even Tesla’s Solar Roof seems to get more love.

If price is the thing you won’t budge on, consider Tesla. By all accounts, Tesla installs quality panels and makes the closest thing there is to a household name in solar storage: the Powerwall.

Where you might miss out is customer service. Discussion online seems to suggest Tesla’s service is a bit of a gamble.

Momentum Solar

All in-house installers

Momentum installs in 11 states without using subcontractors. While using in-house installers doesn’t guarantee a better experience, it does suggest you’re likely to get a more uniform experience from Momentum. The fact that Momentum backs its installations with a 25-year workmanship warranty hints at a strong belief in its crews’ ability. If Momentum is part of your search, consider the warranties against leaks that other companies offer. Momentum’s is five years, which isn’t the best.

Best regional or local solar companies of 2024

The companies on this breakout list may have scored higher than the companies on the national best list. But since they operate in only a few states and are not as accessible as the national providers, we chose to give them a best regional or local callout here.

NRG Clean Power

Best in California and Texas

NRG Clean Power brings one of the solar industry’s most confident approaches to its work, offering a price match and 40-year warranty. NRG Clean Power is a solid bet as long as you live in Texas and California. NRG Clean Power does not offer leases or power purchase agreements, but it does provide solar panel cleaning and roofing services as well as a reliable equipment menu.

Renu Energy Solutions

Great option for the Carolinas

If you live in the Carolinas, Renu offers equipment from well-respected manufacturers and has indicators that its customers are, overall, quite happy. Some of it’s warranties — 10 years on workmanship and 5 years against leaks — are a bit shorter than others in the industry, where they can reach twice as long. Customers gave it an average rating of 4.79 out of five at the Better Business Bureau, which is higher than most companies on the list.

Compare the best solar companies of 2024

This table compares how companies rate against one another by some (but not all) of the criteria we use to judge them. To get the full picture, click the company name to visit their review.

Other solar companies we reviewed

Our experts reviewed other solar companies that don’t appear in our best list above. Given the nature of the solar panel industry, which shifts from state to state and roof to roof, some of these other companies we reviewed might still be a good option for your situation. 

Blue Raven

Now a part of SunPower, another CNET favorite, Blue Raven installs a variety of panels alongside SunVault batteries using all in-house installation teams. Like its parent company and many other solar installers, Blue Raven could offer a price match guarantee and greater price transparency but gets strong marks for customer service. Blue Raven performs installations in 18 states, which makes the company a national operation in its own right.

Primitive Power

Operating on a brokerage model, Primitive Power goes between the customer and installer, promising to offer better prices through a competitive bidding model. Because the business model doesn’t fit our review scoring methodology, Primitive doesn’t get a score from us, but could be a good place to get multiple quotes all at once.

Qcells

Qcells is more of a solar panel manufacturer than a solar panel installer, but representatives for the company will connect you with installers that works with Qcells’ products. The company doesn’t offer the same guarantees or policies most of the installers on this list have, so it doesn’t get a score. If you’re interested in its high-quality, American-made panels, we have a write up with all of the details here.

Smartflower

Smartflower looks like a solar sunflower and might be a beautiful way to install solar panels, but unless you’re trying to advertise your green commitments or find a statement piece for your yard, it’s likely too much money for too little solar.

Sunnova 

Sunnova recently gained loan guarantees from the US government to help low- and moderate-income families adopt solar. If you have less-than-stellar credit, Sunnova might be a good option for you. It’s best to compare quotes, though. It installs a wide variety of batteries and offers some strong warranties. We found in our reporting a history of customer service issues and appears to have lost its Better Business Bureau accreditation — an issue the company told CNET it was working to rectify.

Sunrun

The largest solar company in America, Sunrun offers quality panels, a choice of a couple of batteries and quality inverters. It also offers strong warranties. Most of its business is in solar leases or power purchase agreements. But it is important to note that Sunrun provides stronger warranties for power purchase agreements than purchases.

Tesla

Tesla’s Solar Roof is an exciting way to imagine solar. It’s sleek, it’s low profile, but it’s very expensive. Depending on the size of your roof and your location, it can be several times more expensive than solar panels. 

Trinity Solar

For a while, Trinity Solar was CNET’s top company for customer service and still receives top marks. It also offers quality equipment and warranties, although some of its warranties, like its workmanship warranty, are a bit weaker than other companies.

WindMar Solar and Roofing

WindMar Solar and Roofing is one of the longest-tenured solar installers operating in Puerto Rico and Florida. It installs quality equipment, although customers who finance their system through a loan or enter a lease receive stronger warranties than those who purchase outright.

Solar industry trends: Why go solar now? 

If you’re planning to buy solar panels to avoid rising energy costs and blackouts or to switch to renewable energy, you’re not alone. 

New federal tax incentives have led to massive nationwide growth in solar installations. The country’s largest residential solar market, California, took a massive hit, however, with installation numbers dropping off. The reason: California’s new net metering policy, called NEM 3.0, has seriously hurt net metering incentives in the state, making it take longer to recoup the money initially invested in a solar panel system. Paired with high interest rates that make it harder for people to finance solar systems, it’s led to 17,000 layoffs in the state, according to the California Solar and Storage Association.

Some solar businesses are closing up shop altogether. That includes CNET’s previous highest rated solar company, ADT Solar, which closed its solar business in January 2024.

You can get 30% of the cost of solar panels back on your taxes and participate in local incentives and net metering (where available). The Inflation Reduction Act, passed in 2022, opened up more rebates for energy-efficient home improvements, electric appliances and other renewable energy solutions, which could help you save even more with solar panels.

Improvements in solar panel technology and manufacturing have also brought the prices of solar panels down significantly from where they were a decade ago, and industry experts say that trend should continue. Coupled with newly expanded tax credits, solar panels have never been more affordable. 

Climate change is expected to continue fueling severe weather events that can cause more power outages. Solar panels paired with a backup battery can keep your home powered.

Solar panels can be a costly investment. And since few people can build their own solar panels, you’ll need to carefully research which installer is best for you. 

Factors to consider when choosing a solar installer

Choosing a solar installer is like choosing a contractor for any home improvement project. You have to make sure to ask a lot of questions and compare multiple quotes. Your final decision will likely be based on which gives you the best price and which company gives you the most confidence. CNET outlines some expert tips on choosing a solar installer that’ll make your life easier, though.

Get multiple quotes and compare: This is the single most important step. You can’t know if you’re getting ripped off without checking a quote against something else. To get a sense of the price variety, compare at least three quotes to five quotes from various local installers.
Understand your local incentives: Make sure you know whether your local government and utility have solar-friendly policies that can make solar a safer financial bet.
Read reviews and complaints: Online reviews aren’t the only valid source of truth, but they’re useful for educating yourself on the issues that might crop up and common experiences that customers have had with a company. Google and Yelp reviews are a couple of good places to start reading customer reviews, and you certainly can’t go wrong with referencing the Better Business Bureau.
Talk to your neighbors who have solar panels: Ask your neighbor(s) how well their chosen company communicated, stuck to the schedule, navigated the permitting process and supported them after installation. If the company has a referral program, you could kick a few hundred dollars your neighbor’s way, too.
Check licenses and certifications: You can check the North American Board of Certified Energy Practitioners for certified installers near you. There are other certifying organizations, so ask installers where their licensure comes from.
Ask your installer questions: A reputable installer shouldn’t be afraid of questions. If you feel you’re getting the run-around, ask other installers the same and compare their answers. Your installer should be able to answer all your questions, even the difficult ones. Make sure to ask your installer about project deadlines and how financing works for your particular situation.
Calculate your savings: If a company seems to be promising too much, it might be less than honest. Solar panels can save you a lot of money in the long term, but not in all situations. Find out how to calculate your expected savings with solar panels. If your calculation comes in much lower or higher than a salesperson’s, ask about it. 

What to expect: How does a solar panel installation work?

The process of getting solar panels looks a little different from company to company, but the broad strokes are the same.

After initial contact with the company, someone should visit your home for an inspection. While parts of the design and quoting process might involve looking at satellite imagery, having a professional actually visit your house allows them to take into account trees that might have grown or any other obstacles that shade your rooftop that might not be accounted for in the aerial images. They’ll also be able to assess the health of your roof and whether it needs to be replaced or not and identify any other barriers to going solar.

Some solar installers are adopting AI tools into their solar planning process. It’s yet to be determined AI’s impact on the industry, but experts believe AI use in the solar space will help keep costs down and speed up installation timelines. 

Then the system will be designed, sized, approved by you and permitted. After the company receives permits from the necessary authorities, your installation will be scheduled. Installation typically takes a few days or up to a week depending on the weather. 

Installation for a majority of solar panel systems requires drilling holes through your roof and into the joists that support it. It’s necessary to keep your solar panels securely attached, but you’ll want to ask your solar installer how long it guarantees those penetrations will remain watertight in order to keep your home secure.

Installation will also require new wiring to be installed. Sometimes that means new conduit being attached to the outside of your house. Through our reporting we learned some companies will install it in your attic for free or for an additional charge.

Unless your system is off the grid, you’ll need to get permission to operate grid-tied solar panels from your utility. Once you’ve received permission, you’ll transition to generating energy, monitoring your array’s performance and maintaining your solar panels to keep them up and running during your system’s lifespan. Your new solar panels should last decades, especially if you are locked into a contract with a decent warranty.

While the timeline will vary, it usually takes several months to design, permit, install and switch on residential solar arrays. When shopping around, it’s best to ask what the estimated timeline is. 

Brenda Sangi Arruda/Getty

How much do solar panels cost?

The average cost for a residential solar installation is $2.99 per watt, according to an analysis by Wood Mackenzie. According to those figures, an average 8-kilowatt solar panel system would cost about $23,920. The cost of solar panels varies by location, and the local cost for permitting, inspection fees, labor and more. It also depends heavily on what kind of solar panel system you get and whether you buy a battery to enhance the performance of your solar array. Batteries will add significantly to your price tag, costing around $10,000 or more.

While around $3 per watt is a decent ballpark estimate, the different sources that report solar prices vary in their results. That’s because they get their data in different ways. For example, in the chart below, EnergySage draws its information from quotes provided in its own solar marketplace while Wood Mackenzie’s uses wholesale prices of equipment and interviews with industry figures.

Average national cost of solar panels

*The above estimates are for different periods of time. EnergySage covers the second half of 2023; Wood Mackenzie, the fourth quarter of 2023; and the Lawrence Berkeley Lab, 2022.

The map below pulls data from FindEnergy.com to give the average total cash price, cost per watt and average solar panel system size in states across the country. These prices are representative of your costs before federal, state or local incentives. States in gray lack sufficient data pricing data on FindEnergy.

Solar panel incentives and rebates

There are plenty of incentives to reduce the cost of solar panels or your tax bill. The Inflation Reduction Act increased the federal tax credit for solar panels to 30% and made it available for 10 years. Other local tax exemptions or incentives could be possible, too. If your utility has a net metering program, you could receive credits on your utility bill that will help you save money. Other potential state incentives include property tax exemptions, sales tax exemptions, SREC markets or state tax credits.

How much can I save by going solar?

The answer depends on your own personal energy usage, the solar panel system you choose and a variety of other factors such as net metering policies.

There are a few things you can calculate to help you find out how much you can save. The first is your payback period, in which you calculate the cost of installing solar panels after tax credits and incentives, and divide that by how much money in energy costs you expect to save each year.

That will give you a period, in years, after which your solar panels will have paid for themselves in savings. Your solar panel payback period can vary widely. But after you hit that date, any energy you generate is money saved. 

It’s also entirely possible that solar panels might not save you money but offset only partial costs of your energy bill. Solar savings can depend on factors such as how efficient your panels are, how much sun your panels get, how many panels you have, your electric rates, your state’s net metering policy, and your electric consumption. 

If you want to go solar but either can’t afford the upfront cost of a solar array or you rent your property, community solar might also be a viable option.

Read more: Want something smaller than a whole-home solar system? See our picks for the best portable solar panels and solar generators.

What other solar equipment goes into a solar system?

While the panels are the most visible and well-known component of a solar array, there are other pieces of equipment you’ll need to know — some are necessary parts of your solar panel system, while others are optional equipment that could help you save even more money.

Solar panels

Nearly 100% of the residential solar panels installed today are monocrystalline, according to the Lawrence Berkeley National Laboratory (PDF). Polycrystalline panels are still installed, but at a far lower rate than monocrystalline panels. They’re cheaper but less efficient, but odds are that polycrystalline panels likely won’t be a concern for you.

Solar inverters

Solar panels produce electricity in direct current. Our houses and all the appliances within them use alternating current. We need some way to convert the electricity from DC to AC for use in our houses: that’s where the solar inverter comes in.

There are two main types of inverters in use: string inverters and microinverters. String inverters transform the electricity from a group (or string) of solar panels, all at once. This means you only need one per residential array, typically, but the entire array is affected by the lowest-performing panel. If one of your panels is shaded or damaged, it can significantly reduce the output of the rest of the array. String inverters are typically cheaper to install but come with shorter warranties.

You can find CNET’s pick for best solar inverters here. 

Microinverters are the much more common solar inverters in use today. They operate on the panel level, which means if one is shaded, the rest can keep producing at full capacity. Because they are installed on the roof with the panel, they’re typically a little harder to service but ensure that your solar panel system produces a more reliable amount of energy. Microinverters cost a bit more to install but often come with 25-year warranties.

String inverters can also be installed with power optimizers, which perform a similar role to microinverters. The energy is still translated to alternating current at the central string inverter, but the power optimizer lets panels work independently of each other.

Solar backup battery

Backup batteries are becoming a more popular addition to solar arrays. Time of use rates from utilities (where electricity is typically cheaper when solar panels are producing ample amounts of energy for your households and more expensive during less productive hours) make batteries a more financially feasible choice for many. Solar panels won’t generate electricity during a blackout unless they have a battery that allows them to go off the grid temporarily, a process called islanding.

Backup batteries don’t always make financial sense, so make sure you understand whether or not it does for you before diving in. If you’re hoping to have power during a blackout, the financial calculation may be less important to you.

You can find CNET’s pick of the best solar batteries here. 

How to pay for solar panels

Solar panels come with a hefty price tag so, just like other major purchases, a few financing options have become commonplace.

Paying for solar panels with cash

Paying with cash is the most straightforward and fee-free way to pay for solar panels. You won’t pay interest or loan fees and you’ll lock in the 30% federal tax credit. The obvious downside is that you’ll need to drop a huge chunk of cash all at once, which not everyone can do.

Paying for solar panels with a solar loan

Most solar companies offer financing options, including third-party or in-house loans. If you purchase solar with a loan, you’ll get the federal tax credit, too. Loans of any sort come with interest and fees and it pays to compare fees and interest rates. You can also pay with a loan you bring from elsewhere, like a personal loan from your bank.

Paying for solar panels with a home equity loan

Home equity loans or home equity lines of credit let you borrow money against the value of your house. This can secure you a lower interest rate but introduces some other risks. If you default on a home equity loan, your home can be foreclosed on. Since you’re still purchasing your solar panels, you’ll qualify for the federal tax credit.

Getting a solar power purchase agreement or solar lease

If you see ads touting homeowners going solar with zero money down, they’re probably for solar power purchase agreements and leases. But what is a PPA? It’s the less familiar cousin of a lease.

With a lease or PPA, you don’t actually own the solar panels on your roof. Instead, you agree to pay a monthly fee for the equipment (a solar lease) or to buy the electricity the solar panels produce (a PPA). This means you can go solar without a hefty price tag (and often zero money up front). It’s common for these rates to increase each year, so pay careful attention. If the escalation rate is too high, you may end up saving less money than expected over the lifetime of the deal. Since you don’t own the panels with these agreements, you won’t be eligible for the federal tax credit.

How we evaluate solar companies

Reviewing solar companies in a hands-on way is tough. Each project is as unique as the house it goes on and the family that will use its electricity. To evaluate these solar installers in a meaningful way, we had to focus on what we could measure and what would be useful to you.

We rate companies on three categories of criteria: equipment, warranties and service. 

In the equipment bucket, companies get scored on the panels, inverters and batteries they install. Warranties include the guarantees on the panels (which typically come from the manufacturer), workmanship and weatherization against leaks. Companies gain points for service for offering a price match, a meaningful level of price transparency and a well-rated app for monitoring solar production. They lose points for major customer service issues (lawsuits, investigations or obvious reputations for shoddy service). We’ll always detail these in the review.

You can read a detailed look at how the scoring breaks down.

We don’t consider the average price of a company’s installations in their score. Average prices are hard to find and compare place to place (or even roof to roof). Companies are often slow to disclose it, too. We also leave out information that’s easy to find, but not useful to you, like how many states a company operates in.

Solar panel FAQ

Are solar panels worth it in my state?

Solar panels will likely be worth it, depending on the details of your specific situation. If you use very little energy or have very cheap energy, you won’t be saving as much money each month and it will take longer for your panels to pay for themselves. If you live under deep tree cover, rooftop solar panels likely won’t generate enough electricity to be worth it. 

Solar can pay off in energy savings for decades. Lowering the cost with rebates and tax credits will help pay off your solar panels faster. How you pay for your solar panels will affect that calculation, too. It’ll take longer to recoup your costs if you take out a loan, which will accrue interest and come with fees. You can calculate your payback period if you know the cost of solar panels after rebates and how much you’ll save on energy costs each year.

Most importantly, be sure you’re saving money by shopping around and finding the right solar panel system at the right price.

How many solar panels do I need?

This answer is specific to you and depends on how much energy you use and how much sunlight you get. Depending on your local regulations and electricity rates, installing more panels than you strictly need may not be allowed or even worth it.

To calculate how many solar panels you need, determine your average daily energy use in kilowatt hours. Divide that by the peak sun hours your home gets to find how much solar capacity you’ll need to install in kilowatts. Divide that capacity by the size of your solar panels (400 watts, or 0.4 kilowatts, is a common size) to get the number of panels you’ll need.

This is just a rough estimate and a reputable solar installer should be able to offer you a rationale for the number of panels they propose installing.

Net metering is the way that utilities compensate you for energy your solar panels generate but you don’t use. Since this energy flows back to the grid for someone else to use, it’s fairly common for utilities to offer you bill credits for that energy to offset what you buy from them. These credits save you even more money on electricity than solar panels would without.

Net metering will look different from utility to utility and the incentive has been challenged and even eliminated in some states, like Indiana. A 2023 change in net metering in California caused the number of solar installations to drop significantly.

How long do solar panels last?

If you buy solar panels today, there’s a good chance they’ll be under warranty for 25 years. You’ll often see that listed as the lifespan of the panels, but that’s not quite accurate. That warranty covers production of your solar panels. Solar panels lose their ability to produce solar electricity as they age for any number of reasons, so a warranty will guarantee a certain level of production after a certain number of years. For example, Q Cells offers a 25-year warranty, which guarantees that your panels will produce at 86% of their rated capacity at that point.

This doesn’t mean those solar panels die at the end of 25 years, they’ll just produce less. Solar panels can produce well after their warranty expires, though given that large numbers of solar panels are just now being installed, we’ll continue to get a better idea of how they age in years to come.

Should I hire a solar panel installer?

While skilled do-it-yourselfers might be able to pull off a solar panel installation, it’s definitely not recommended. Going through a reputable and licensed solar installer gives you a number of protections. Installing solar panels is not as simple as plugging in a large appliance. A qualified solar installer will be able to navigate local code and ordinances and ensure that the warranty on the panels remains intact. They will also be able to tell you if you need a new roof or other upgrades before installing solar panels.

A solar installer will also be able to design your solar system to best fit your goals and habits by identifying the most productive locations on your roof and angling panels to collect the most sun. Further, your installer should be able to help you troubleshoot any problems that arise after installation.

How do I know if the quote I have is a good one?

The best way to tell is to get multiple quotes. With a purchase this big, you should get several, including one or two from local installers who might be able to offer you greater choice.

There are also resources from the federal and many state governments to guide you through the process. You can look out for a few red flags from salespeople, too. 

Are local solar installers a good option?

Local installers typically have less costs for advertising and sales than large, national corporations. That represents possible savings that could be returned to customers. On the other hand, with a long-term investment like solar panels, it may feel safer to have the backing of a large corporation. Larger companies may be able to offer cheaper prices due to the volume of installations they do.

When you’re gathering quotes for a solar panel installation, be sure to contact local installers, too. The solar industry is a competitive one, and checking around could save you thousands.

Will solar panels work in my climate?

Identical solar panels will produce different amounts of electricity when they’re exposed to different levels of sunlight. Solar panels in sunnier places (like the American southwest) with more direct sunlight (like in the south) will produce more electricity, but other factors make solar a good deal for homeowners.

New England has one of the highest regional adoption rates for residential solar in the US. That’s not because it has a ton of sunshine year round, but because it has favorable solar policies, like net metering and rebates. Solar panels might make financial sense even if they’ll be installed under frequently cloudy skies. 

Can I get the federal tax credit?

Correction, Jan. 31, 2023: An earlier version of this article misstated the Better Business Bureau’s grading process. Any company can receive a grade from the Bureau, regardless of whether it has paid to go through the accreditation process.