SunPower Panels Review: Costs, Quality, Warranties & More (2025)

EcoWatch Reviews Methodology

I have personal experience with SunPower’s solar panels. After months of research, I purposefully chose a SunPower dealer when I went solar to get access to their top-of-the-line Maxeon panels. The opinions and analysis I present in this review are informed by firsthand experience living with and benefiting from the panels I’m reviewing. I’ve also done analyses of and comparisons with my neighbors who installed different panel brands — Q Cells and REC — and despite our homes being in virtually the exact same sunlight conditions, I can confidently say that the Maxeon panels I chose outperform the other brands.

Much of the information I present in this review comes from the analysis I did when I was considering what panels to purchase for my own home. To complement my subjective experience — which is only one data point — I’ve dug into the technical specifications and efficiency ratings to see how SunPower panels objectively compare to their competition. I’ve also compared costs and other financial factors to determine the value SunPower panels provide over the long term.

To make all this information easier to understand, I’ve packaged it into easily digestible categories based on EcoWatch’s solar panel review criteria. The EcoWatch rating for solar panels is based on a proprietary scoring system that considers numerous factors split into seven main areas for comparison. The following list describes the categories EcoWatch uses to rate solar panels and explains how I determine my scores for each category:

• Efficiency: I examine the average and maximum efficiency ratings, as well as the power tolerance, to see how much electricity the panels can generate in real-world conditions. Higher efficiency means more power and more savings over time.
• Durability: Looking at metrics like the first-year and subsequent-year degradation rates, wind load, and snow load, I assess how well the panels will stand up to the elements over their 25- to 40-year lifespan. Durable panels will produce more consistently in the long run and leave you with fewer headaches.
• Warranty: The length and coverage of the equipment and performance warranties show how much faith SunPower has in its products. Stronger warranties provide better long-term protection for your investment.
• Price: I compare SunPower’s prices to those of other panel brands to see how much of a premium the company commands. This also helps me determine if the higher costs are justified by the long-term performance when considered alongside the other specifications.
• Temperature Coefficient: How well the panels perform in extreme heat is an important consideration, especially if you live in a hotter climate. A lower temperature coefficient means the panels can still perform efficiently on scorching days, which is when you’ll often have higher electricity demands for cooling your home.
• Sustainability: I look at factors like the materials used, the manufacturing process, and end-of-life recycling options to gauge how environmentally friendly the panels are. Greener practices are better for the planet and the laborers in the industry and become more important as the solar industry expands.
• Appearance: While less important than performance, in my opinion, the aesthetics of the panels matter to many homeowners. I assess the look and style of SunPower panels compared to other options. This category is highly subjective, so I try to present the facts primarily rather than my own opinions on aesthetics.

In addition to assigning scores across these key technical categories, I also rely on my industry expertise and insights to provide context on what sets SunPower apart in the increasingly competitive field of solar panel brands. My goal is to arm you with the facts you need to determine if SunPower’s panels are the right choice for your home’s solar system.

SunPower Panels: Most Efficient

What I Like About SunPower Panels

When it comes to assessing solar panels, efficiency is the most important factor, in my opinion. The more electricity your panels can generate from the sunlight that hits them, the more power you’ll have available and the more you’ll potentially save on utility bills over the lifespan of your solar system. SunPower’s Maxeon line has been the industry leader for many years when it comes to squeezing the most power out of each square foot of photovoltaic cells. While SunPower’s lead has narrowed over time, its Maxeon panels are still the most efficient available on the residential market in terms of the average efficiency of its panels.

SunPower panels used to have the highest max efficiency, as well, but the patents on much of the technology that made this possible expired, and many of its competitors caught up. Maxeon panels are still outstanding, but they actually got edged out of the top spot by LONGi panels in 2023, based on our scoring system.

I was drawn to SunPower when I was shopping for my own home solar system because no other widely available brand could match the performance specifications of the Maxeon panels at the time. With an average efficiency rating of 22.3%, Maxeon sets the standard for residential solar power production. The company’s top-of-the-line panel — Maxeon 6 — boasts an efficiency of 22.8%, which gives it a significant edge over most other panels on the market — over all brands, in fact, except Jinko Solar and Canadian Solar.

The practical benefit of those industry-leading efficiency ratings is more net power production over time, especially in less-than-ideal roof and weather conditions. If you have limited space on your roof, obstructions that cast shadows during parts of the day or don’t have the optimal southern exposure, more-efficient panels like SunPower’s can help compensate for those shortcomings. You’ll be able to wring the most possible power out of whatever sunlight you do get.

SunPower’s panels also have an excellent positive power tolerance of +5%, which means they’re regularly tested to perform 5% above their listed power rating. They also have a negative power tolerance of -0%, which means that they perform at least as well as their rating states. Some panels will test to have a nonzero negative power tolerance, which means they sometimes deliver less power than their rating suggests. With Maxeon panels from SunPower, you don’t have to worry about your system underperforming its advertised production, and you may even see greater power production.

Another aspect of SunPower’s Maxeon panels that I appreciate is the stellar 0.25% subsequent year degradation rate. All solar panels become gradually less efficient over time, but Maxeon panels have one of the lowest degradation rates in the industry. That slow decline means they’ll not only start out with above-average efficiency but will also continue performing close to their initial efficiency level even 20 years or more into their operating life. Maxeon panels will save you more money in the form of reduced electricity bills over their lifetime than lower-efficiency panels that degrade more quickly.

What I Don’t Like About SunPower Panels

As much as there is to rave about when it comes to SunPower’s panel efficiency, there are a few important downsides I should point out.

First, SunPower’s top-notch performance comes at a steep price. SunPower’s panels are consistently among the most expensive on the market on a per-watt basis. Paying a premium for higher efficiency can make sense if you want to maximize long-term production and savings, and I personally think the premium is well worth it. However, the up-front cost can be hard to swallow and may put SunPower out of reach if you’re on a tight budget. It also means that it will take longer for your panels to pay for themselves if you finance your purchase with a loan (more on that later).

Based on our data, SunPower/Maxeon panels cost around $4.00 per watt, putting the average solar array that’s 9 kilowatts (kW) at $36,000 before any incentives, or $25,200 after the federal investment tax credit (ITC). The average cost of a tier-one panel is around $3.33, which means choosing SunPower panels will cost you an additional $6,000 up front, or an additional $4,000 after the tax credit compared to most other panel options.

Unfortunately, the efficiency edge that once helped justify SunPower’s premium pricing has been gradually eroding as competitors catch up. A few years ago, SunPower was the only option if you wanted panels that exceeded 22% average efficiency. But now, other tier-one brands like Canadian Solar and REC have narrowed the gap with average efficiencies of 22.0% and 21.6%, respectively. Those panels sacrifice a bit of performance but often cost substantially less than SunPower’s, potentially negating the long-term benefit for some customers. Canadian Solar now surpasses SunPower in terms of maximum efficiency rating, with its highest-rated panel reaching 23.1% efficiency compared to SunPower’s best of 22.8%.

Another negative that I discovered in my research is that SunPower’s customer service doesn’t always live up to the premium price point. Many of the 1-star reviews from frustrated customers mention difficulties getting in touch with customer support to address product or installation issues. To be fair, most large-scale installers and panel brands seem to struggle with inconsistent customer service, based on the reviews I’ve analyzed. But SunPower doesn’t appear to be significantly better than the norm despite its positioning as a premium company. I haven’t personally experienced difficulties in my communication with the company as either a prospective or current customer, but my experience is just one data point.

Finally, while this doesn’t affect the performance of the panels themselves, it’s worth noting that SunPower doesn’t manufacture its panels in the United States. Maxeon makes its cells in the Philippines and Malaysia before assembling them in Mexico. For customers who prioritize buying American-made products, that could be a deal-breaker. To SunPower’s credit, though, they are one of the few major solar manufacturers who are transparent about the sourcing of their components. I’ll discuss both points in more detail in a later article section on sustainability.

SunPower Panels’ Efficiency

22.5/25

A solar panel’s efficiency is one of its most important characteristics. How efficiently your solar panels convert sunlight to electricity determines how many panels you need to buy to offset your electricity usage and how much you stand to save over your solar system’s useful life. Panels with lower efficiency require more individual cells to produce the same amount of energy, which usually means spending more money to buy more panels if you want to reach 100% offset. Low-efficiency panels also save you less money over time since the total amount of energy they generate is significantly less than higher-efficiency panels.

Unfortunately, there isn’t a single efficiency rating you can look at to determine a company’s overall panel efficiency. The four main specifications you need to pay attention to when you’re comparing solar panels in terms of efficiency are the following:

• Average panel efficiency: This measures the average efficiency of all the panels that a company installs. It’s a quick and dirty measure for estimating whether a company offers high-efficiency or low-efficiency panels in a general sense. Efficiency ratings don’t directly translate to savings because two companies that have the same average panel efficiency may offer panels with different degradation rates. I’ll discuss that wrinkle in more detail in an upcoming article section.
• Maximum panel efficiency: This is the highest efficiency rating a company offers on any of its panels. If you’re interested in maximizing your system’s efficiency, this is the rating to which you should pay the most attention. A higher efficiency rating means greater savings over time, so a company’s maximum panel efficiency tells you, roughly speaking, how much you can save over time. Note, however, that you need to consider this metric in combination with the degradation, as a panel that starts with a high efficiency but degrades more quickly could end up producing less and saving you less over time than a panel that starts a bit lower but has below-average degradation rates. We give companies with maximum panel efficiency ratings of 22.8% or greater the highest score for this category.
• Positive power tolerance: A panel’s positive power tolerance rating measures how much more energy a panel might generate compared to its listed power rating. In general, the higher a panel’s positive tolerance, the better, but we consider anything with a rating above +3% to be good. Panels with ratings greater than +5% get a perfect score for this factor.
• Negative power tolerance: A panel’s negative power tolerance rating is similar to its positive rating and measures how much a panel may underproduce compared to its nameplate rating. Panels with ratings of -0% are guaranteed to produce at least as much energy as their efficiency ratings imply. Panels must have a negative power tolerance rating of 0% to receive a perfect score in our rating system.

Maxeon panels score well in all of these subcategories, earning an overall score of 22.5 out of 25 when it comes to efficiency. SunPower’s average panel efficiency rating is 22.3%, which gives it the maximum number of points for that sub-category, and first place in our rankings for this metric. Similarly, SunPower’s most efficient panel — the Maxeon 6 series — has an efficiency rating of 22.8%, which earns it full marks in that subcategory as well. It’s only behind two other companies — Canadian Solar and Jinko Solar — when it comes to max efficiency.

SunPower solar panels have solid tolerance scores, with a positive tolerance of +5% and a negative tolerance of -0%. The negative power tolerance of 0% means that your panels will perform at least as well as their labels claim. You don’t have to worry about unexpected underperformance because of the negative power tolerance rating of 0% and you might enjoy higher production numbers than you expect, thanks to the positive tolerance rating of 5%.

The only point SunPower panels lose when it comes to efficiency is due to its positive tolerance rating. We reserve top marks for panels with greater than 5% positive power tolerance. SunPower’s score of 5% puts it just under the threshold it needs to earn full points.

You might wonder why maximizing efficiency matters since, after all, you can’t use any extra energy your panels generate above and beyond what you need to power your home. Well, actually, you can — sort of. Many states have net metering or net energy metering (NEM) programs that let you send any extra electricity your panels produce back to the power grid. You can call on that power at night or on cloudy days when your panels underproduce at no cost. If you live somewhere with a net metering program, maximizing your system’s efficiency means greater savings and a shorter payback period on your panels.

Unfortunately, some states are starting to make their NEM programs less favorable to residential producers or even eliminate their net metering programs altogether. California transitioned from NEM 2.0 to NEM 3.0 last year, reducing the amount utility companies have to pay for the energy your panels produce by 75%. California is somewhat of a trendsetter when it comes to solar policy, so it’s likely that other states will follow suit.

If that happens, or if your state just doesn’t have a net metering program, you can still take advantage of any excess energy your system generates by installing solar batteries.

The take-home point for the efficiency criteria is that SunPower’s solar panels are great if you want to maximize your solar system’s efficiency and have a flexible budget, and they’re especially good for long-term savings if you have batteries installed or access to a one-to-one NEM program. I’ll discuss cost in a later article section, but from a pure efficiency perspective, you can’t go wrong with Maxeon panels from SunPower.

SunPower Panels Durability

14/20

When you’re investing tens of thousands of dollars in a solar system that’s supposed to last for 25 to 40 years, you need to have confidence that the panels can withstand the test of time and the elements. You don’t want to be replacing panels every few years because they can’t handle the weather in your local climate.

Wind, snow and hail pose serious challenges for solar panels and lower-quality panels can easily sustain damage even from relatively mild storms. Fortunately, SunPower’s Maxeon panels are robust and capable of holding up against most extreme weather conditions.

Here’s a quick summary of the specs I’ll discuss below for SunPower’s Maxeon panels:

• First-year degradation rate: 2.0%
• Subsequent annual degradation: 0.25%
• Maximum wind load: 5,400 Pa
• Maximum snow load: 5,400 Pa

Let’s start with arguably the most important measure of a panel’s durability and longevity: its degradation rate. Even the highest-quality solar panels lose efficiency as they age. Minimizing the amount of efficiency panels lose over time is an important area of research, and manufacturers strive to keep degradation rates low to extend their panels’ useful lifespans.

Solar panels lose the most efficiency during their first year in operation. The first-year degradation rate of a panel indicates how much efficiency the panel loses during its initial 12 months of use as it’s exposed to sunlight and the elements. SunPower’s Maxeon panels have a first-year degradation rate of 2.0%, which is a bit higher than that of panels from industry leaders such as LONGi and Canadian Solar, which manage to lose just 1.0% during the first year.

SunPower’s above-average first-year degradation rate puts a bit of a damper on its high initial efficiency rating since it loses a higher fraction of its starting efficiency than it would with a lower rate. This brings me to a point I alluded to in a previous article section: a panel’s efficiency rating tells only part of the story.

A panel with a high starting efficiency rating can wind up producing less energy than a panel with a lower initial efficiency rating if it has a higher degradation rate. Maximizing your system’s efficiency — and therefore your savings — requires careful consideration of a panel’s starting efficiency and degradation rates. Luckily, the first-year degradation rate only applies to a panel’s first year in operation and panels lose less efficiency per year after the first year. That rate is called the subsequent-year degradation rate.

SunPower’s subsequent-year degradation rate ( measuring the efficiency decline each year from the first year onward) of 0.25% is tied with those of Panasonic and REC for the lowest in the industry. It. At 0.25% per year, SunPower panels will still retain 92% of their original rated capacity after 25 years and over 87% of it after 40 years. That’s about 5% higher than most competitors can boast, according to our research, which translates to substantially more electricity production over the decades-long lifespan of the system — which, of course, means more money saved on your utility bills.

In addition to maintaining their efficiency over time, SunPower panels are also designed to withstand the mechanical stresses of extreme weather conditions. The two most important weather-related panel specs are the maximum wind load and the maximum snow load the panel can withstand without taking damage.

The maximum wind load indicates how much upward air pressure the panels can tolerate before incurring damage. It’s measured in Pascals (Pa), with each Pa representing a tiny pressure in pounds per square inch (psi). SunPower’s panels boast a maximum wind load of 5,400 Pa on both the front and back sides, which corresponds to 0.78 psi.

That’s a hard number to wrap your head around. To put that figure in context, 5,400 Pa equates to sustained wind speeds of approximately 210 mph. For reference, a Category 5 hurricane has sustained winds of 157 mph or higher. So, SunPower panels are built to withstand pretty much the worst Mother Nature can throw at them in terms of wind. You can use this wind load calculator to see how wind speeds convert to pressures yourself.

The maximum snow load measures how much downward pressure the panel can handle from the weight of accumulated snow sitting on top of it. Again, this is measured in Pascals, and again, SunPower’s rating of 5,400 Pa is one of the highest in the industry. That 5,400 Pa snow load translates to roughly 55 lbs. per square foot. Given that each Maxeon panel has a surface area of about 20 square feet, that means a single panel can support more than 1,000 pounds of snow.

To put that load-bearing capacity in real-world terms, you’d need over four feet of wet, heavy snow to approach the weight limit of SunPower panels. In practice, it’s difficult to accumulate that much snow because of the steep slope at which solar panels sit on your roof. The actual snow depth that accumulates on the panels is only a fraction of the snowfall amount, as most of the snow slides off under its own weight. The bottom line is that unless you live in an extremely snowy and cold climate, the probability of your SunPower panels getting damaged due to snow load failure is basically zero.

Overall, SunPower’s Maxeon panels are among the most durable and robust solar panels on the market. The ultra-low subsequent-year degradation rate means the panels will keep churning out close to their rated power for decades to come, while the high maximum wind and snow load ratings provide peace of mind that they can survive even the harshest storm conditions. Despite a below-average first-year degradation rate, SunPower still scores well in the Durability category. I personally haven’t had any issues with weather-related damage, although I do live in a relatively moderate climate, so there’s not much of a threat to begin with.

SunPower Panels Warranty Coverage

20/20

Even though SunPower’s panels are highly durable, they’re not completely invulnerable to damage or malfunctions. A strong, comprehensive warranty package provides peace of mind that you won’t be left footing the bill for expensive repairs or replacements if something goes wrong years down the line.

SunPower offers the longest and most robust warranty terms in the solar industry, backing up its durable panels with a strong equipment warranty and a strong production guarantee. SunPower’s warranties played a major role in my decision to go with the company when I was deciding what solar panels I wanted to use for my own home’s solar system.

Here’s a quick look at the coverage you get from SunPower when you purchase its solar panels:

• Equipment warranty term: 40 years
• Equipment warranty coverage: Materials and workmanship
• Efficiency warranty term: 40 years
• Efficiency warranty coverage: 98% of initial after one year, 92% of initial rated power after 25 years and 87% of initial after 40 years

Let’s start with SunPower’s product warranty, which covers any defects in materials or workmanship in the panels themselves. Most tier-one panel manufacturers offer a product warranty of 10 to 25 years, with 25 years being the standard. SunPower blows them out of the water with an industry-leading 40-year product warranty. That means if any part of your panel or related equipment fails due to a manufacturing defect or faulty component within 40 years of your purchase, SunPower will repair or replace it for free.

That coverage includes your rack, inverters and wiring, which isn’t usually the case with other companies. Many solar companies break up their warranties into separate coverage for each component, which lets them cover certain elements, such as inverters or wiring, for shorter periods than the panels themselves.

To put the length of that product warranty in context, consider that the average lifespan of a residential solar system is approximately 25 to 30 years. SunPower is one of the only companies in the solar industry that covers its panels for longer than their expected lifetime. It can offer such a long product warranty because of the durability and reliability of the Maxeon panels the company uses. It gives me peace of mind knowing that the company that installed my panels believes in them enough to cover them for 40 years. And since most solar arrays pay for themselves in around 11 years, that means nearly three decades of net savings — equating to tens of thousands of dollars, based on our research.

In addition to the physical materials and workmanship of the panels, SunPower also covers the power output capability. Many panel manufacturers only guarantee the actual electrical production of their panels through a separate performance warranty (more on that in a moment). SunPower, however, combines the two under their single overarching product warranty, simplifying the claims process for any power issues.

SunPower’s performance warranty guarantees the amount of electricity the panels will generate over time as your panels inevitably degrade and lose some efficiency. SunPower’s performance warranty terms are the best I’ve seen, guaranteeing a minimum of 92% of the initial rated power output after 25 years, and 87% after the full 40-year warranty term.

To translate those percentages into real-world terms, if you have an average-size 9-kilowatt (kW) SunPower system installed today, the performance warranty guarantees it will still be generating at least 8.3 kilowatts in 2049 and 7.8 kilowatts in 2064. No other major panel brand offers that degree of long-term protection for your system’s electricity production.

There is one slight nuance to SunPower’s performance warranty. The terms of the warranty state that it’s a “peak power” guarantee based on the specific wattage of each individual panel, rather than a system-wide kilowatt threshold, as I assumed for illustrative purposes in the previous article section. If your system underperforms and you have to file a claim, SunPower will test each panel individually and provide compensation for any excessive degradation it finds. In practice, this shouldn’t matter much for your system’s real-world production statistics.

The bottom line is that SunPower’s industry-leading 40-year product and performance warranty offers unparalleled peace of mind for your solar investment. No other panel manufacturer matches the length or scope of their coverage. When coupled with the proven durability and reliability of their Maxeon panels, it’s hard to beat SunPower’s warranty protection.

SunPower Panels Cost

2/20

If it sounds like SunPower panels are too good to be true so far, this is where things come crashing back down to Earth. Simply put, SunPower panels are premium products that fetch premium prices. The high efficiency and excellent warranty coverage you get from SunPower come with a sizable price tag. Let’s break down exactly how much SunPower panels cost and discuss whether a SunPower system is worth the cost.

SunPower’s Maxeon solar panels are some of the most expensive residential solar panels on the market today. The average cost of a Maxeon solar panel is around $4.00 per watt, according to our research, which is about 20% higher than the industry average of $3.33 per watt for tier-one monocrystalline solar panels. For an average 9-kW system, that means you’ll pay around $36,000 for your panels if you choose SunPower.

According to our research, the average price of a 9-kW system in the United States is $29,970 — before incentives, which I’ll discuss in a bit. SunPower’s systems cost 20% more than average, which is a sizable amount of money for a major purchase like rooftop solar panels. Whether the premium price is worth it depends on your priorities and what you hope to get from your solar system.

On the one hand, SunPower’s panels are more efficient and more durable than most other solar panels, so you’ll produce more energy over the lifetime of your system than you would with cheaper panels. SunPower’s industry-leading warranty also provides more peace of mind that your investment will be protected for decades to come. It’s hard to put a price on eliminating worry, so you’ll have to decide how much robust coverage and a solid power-production guarantee are worth to you. I personally think the panels are worth the price tag, which is why I bought them for my own home.

On the other hand, the solar industry has advanced rapidly in the past few years, and the performance gap between SunPower’s products and products from competitors has narrowed considerably. LONGi, Canadian Solar and REC, for example, sell panels with efficiencies that come within a few percentage points of SunPower’s industry-leading panels for about a 20% lower cost. REC panels have an average efficiency rating of 21.62% and only cost $3.67 per watt, based on our data.

The point is that SunPower’s panels will provide more than enough energy production and savings in the long run, but other manufacturers offer products that come very close to SunPower’s performance at a significant discount. Canadian Solar’s most efficient panel has an efficiency rating of 23.1%, which makes it slightly more efficient than SunPower’s most efficient panel, which has a rating of 22.8%.

Ultimately, SunPower’s panels are the best choice for people who are willing to pay top dollar for the absolute best combination of solar technology and warranty currently available. If you’re looking for the best value or don’t have the budget to afford SunPower’s offerings, there are plenty of other high-quality options at lower prices.

Savings Potential

Speaking of value, it’s a good time to break down what, exactly, an investment in SunPower panels will get you in terms of long-term savings. The average American homeowner saves $31,513 over the lifetime of their solar system after accounting for the system’s up-front cost. Those savings come primarily from reduced energy bills, which add up to more than the cost of the system over time.

Maxeon’s high-efficiency panels will help you maximize your savings by generating more electricity than other panels of the same size in the same conditions (including sunlight, latitude, and roof angle). Just how much more you’ll save depends on several factors, including your location, your roof’s layout and your energy usage patterns.

I already touched on net metering in the article section on efficiency, but it’s worth noting here that net metering (NEM) plays a major role in how much solar can save you, regardless of which panels you choose. NEM refers to the practice of utilities crediting homeowners for excess solar electricity their panels produce. Essentially, any excess energy you produce is fed into the grid, and you accumulate credits with your utility company that you can use when your panels aren’t producing enough energy, such as on cloudy days or at night. One-to-one NEM ensures that you’re credited for the full retail price of the energy your panels produce.

You can watch the short video below for a brief description of how net metering works.

Many states and utility companies around the country are starting to reduce their NEM credits, which means that the electricity your panels generate might be worth less in the future than it is now. There’s a bit of a “solar rush” going on as savvy homeowners try to lock in more favorable NEM rates before their utility companies reduce or eliminate them. Your SunPower dealer can tell you more about the NEM situation in your area and how it might affect your savings. If you have a net metering program in your state, you will be grandfathered in at the current rate, so you don’t have to worry about what happens if your state repeals or changes its net metering program in the future.

If you don’t have a net metering program in your area, you can get a similar benefit by adding solar batteries to your system. Batteries allow you to store the extra energy your system produces, effectively replacing a full-retail-price net metering program. Batteries cost between $6,000 and $12,000 each, according to our research. The total depends on what make and model you choose, and, in my opinion, they’re not worth it if you have access to net metering unless you need power during blackouts to run lifesaving medical equipment.

Many SunPower dealers install either the company’s own SunVault batteries or Tesla’s Powerwall batteries. Both options let you pull power from the batteries when your system isn’t meeting your home’s electricity needs. They also act as an emergency backup during power outages. If you purchase the right size batteries for your home’s energy consumption, you can run essential systems like HVAC systems and your refrigerator for around two weeks during a blackout with no additional energy input from your panels, based on our research. I ran a personal study with my system and found that, with the Powerwall’s islanding inverter, my panels could continue to charge my batteries during a blackout, effectively giving me limitless time off the grid.

SunPower also offers the Enphase Battery System without backup. This system doesn’t provide emergency power during outages — as the name suggests — but still helps you save money by storing energy when your system is overproducing. These batteries tend to cost less than others that do provide emergency backup power because they lack system controllers that regulate power during outages. They’re helpful for optimizing grid usage in areas with time-of-use electricity plans.

SunPower Financing Options

There’s no denying that solar systems are expensive, in general, and SunPower systems with Maxeon panels are at the upper end of the solar panel price range. Luckily, SunPower offers multiple financing options to help homeowners afford the cost of their systems. You can, of course, purchase your system outright if you have the cash on hand. Paying in cash will net you the highest lifetime savings since you won’t have any financing fees or interest to pay. If you do have to borrow money to afford your panels, SunPower works with multiple financing partners to offer solar loans with varying term lengths, APRs and down payment requirements.

Solar loans function similarly to any other home improvement loan in that you borrow money from a lender, pay for your system, and then pay the lender back according to the terms of your loan agreement. Your SunPower dealer can tell you about loan options in your area and help you choose the financing plan that works best for you. Choosing a loan over a cash payment will reduce your overall savings since you’ll pay interest. Broadly speaking, you should expect to pay about $5,000 in interest over the course of a standard solar loan, based on our research, which brings the lifetime net savings of $31,513 we discussed earlier down to around $26,000.

SunPower also offers solar leases and power purchase agreements (PPAs) as alternatives to cash purchases and loans. With a solar lease, SunPower installs panels on your roof at no up-front cost to you, and you pay the company a monthly fee to “rent” the system. The lease payment will be less than what you currently pay for electricity, so you’ll still save money every month, just not as much as you would if you owned the system outright. Solar leases are attractive because of their low barrier to entry, but they limit your savings to around $5,000 over the lifetime of your agreement. Paying more up front for a loan or cash purchase will allow you to realize five to 10 times more in savings over the long run, according to our research.

PPAs are similar to leases in that the solar company installs panels on your roof for no money down. The difference is that with a PPA, you pay the solar company for every kilowatt-hour (kWh) of energy the panels on your roof produce rather than a flat monthly fee. PPAs reduce your electricity costs somewhat, but your savings will be even lower than with a lease, around $4,000 in most cases, or about 10 times less than what you’d save by purchasing the system yourself.

If the raw savings difference alone isn’t enough to convince you to avoid leases and PPAs, it turns out that only systems purchased in cash or financed with a loan are eligible for tax incentives. The federal government and many state governments offer incentives to homeowners who invest in solar energy. These incentives can reduce the effective cost of your system by thousands of dollars. I discuss them in detail in the next article section.

How Can You Save Money on SunPower Panels?

Another important consideration when choosing how to pay for your solar panels is the federal solar tax credit (ITC). The ITC credits you for 30% of the cost of your solar energy system on your federal income taxes. The average 9-kW system that we’ve been using as an example would normally cost $29,970, but the ITC would effectively reduce the cost to $20,979, effectively saving you $8,991. That’s a huge incentive, but there’s a catch: you can only claim the ITC if you purchase your solar system with cash or a loan. If you choose to enter a lease or PPA, you are not eligible to claim the credit since you won’t actually own the system yourself.

Some states have similar tax incentives, so you should check with your state government or visit the Database of State Incentives for Renewables & Efficiency (DSIRE) website to learn about the incentives available to you. New York, for example, offers a state tax credit worth 25% of your system’s total cost up to $5,000, and as a New York resident I was able to take this in addition to the ITC, which was a big deal.

The bottom line is that SunPower’s panels aren’t the cheapest option available, but they do offer the highest performance and durability. Whether the tradeoff between up-front costs and long-term savings is worth it is up to you. If you do decide that SunPower’s panels are right for you, purchasing them with cash or a loan will maximize your savings and give you access to the substantial savings available through the ITC.                                                                                                  

SunPower Panels Performance Based on Location

7/10

One complicating factor I haven’t covered yet is how your panels perform overall based on location and conditions in addition to efficiency ratings and performance stats like power tolerances. Real-world performance depends on a few details about your home rather than just on panel specifications. To get the most out of your solar panels, you need an unobstructed south-facing roof with enough surface area to hold enough panels to offset your electricity usage.

Another location-based factor you need to consider is the average temperature in your area. Solar panels don’t perform as well in hot climates due to increased resistance throughout the system. How dramatic this effect is depends on something called the temperature coefficient.

A solar panel’s temperature coefficient tells you how well it will perform in different climates and locations with different average temperatures. It measures how much a panel’s power output decreases for every degree Celsius the temperature rises above 25°C (77°F), which is the standard temperature at which solar panels are tested and rated.

As the ambient temperature rises, solar panels produce less electricity due to increased resistance in the circuit. Electrons that are normally flowing freely through the solar cells encounter more resistance, which causes some power to dissipate, reducing the panel’s total power output. If that all sounds a bit too abstract to make sense of, don’t worry. I’ll clear things up with an example using the temperature coefficient for Maxeon panels.

SunPower’s temperature coefficient is -0.27%/°C. This means that for every degree Celsius above 25°C, the panel’s output decreases by 0.27%. For context, the industry-standard temperature coefficient is -0.29%/°C, so SunPower panels perform slightly better than average in high temperatures. However, some other leading brands like LONGi (-0.23%/°C), Panasonic (-0.24%/°C), REC (-0.24%/°C), and Q Cells (-0.24%/°C) have even lower temperature coefficients, meaning they handle heat even better.

Still, SunPower’s temperature coefficient of -0.27%/°C is quite good and earns it a score of seven out of 10 in this category. To really hammer home the point, let’s consider how SunPower panels would perform on a hot summer day of 35°C (95°F), which is 10°C above the 25°C standard.

With a temperature coefficient of -0.27%/°C, SunPower panels would see a power loss of:

10°C x -0.27%/°C = -2.7%

So on a 35°C day, a SunPower panel would be operating at 97.3% of its current capacity. For a 400-watt panel, that means it would be producing about 389 watts under those hot conditions.

In very hot climates like the Southwestern United States, where summer temperatures regularly exceed 40°C (104°F), that power loss becomes more significant:

15°C x -0.27%/°C = -4.05%

At 40°C, a SunPower panel would operate at 95.95% of its rated output, so that same 400-watt panel would now produce around 384 watts.

A few watts here and there on hot days may not sound like much, but over the course of a year, these small differences in daily output can add up. In a single day for a system that generates 10 kW, a 4% dip would still yield 9.6 kW. Not a huge deal. But over a 3-month summer season, a 4% drop could bring you from 900 kW down to 864 kW. Given the average cost of a kWh in the U.S. — around $16.68 cents — that’s a seasonal loss of over $144. And keep in mind that, while it might not be 104°F outside, your panels, which are all black and usually in direct sunlight, can easily exceed that temperature.

If you live in a hot climate, you’ll get more electricity out of your panels if you choose a brand with a lower temperature coefficient like LONGi or REC. However, SunPower’s temperature coefficient is still better than average, so its panels are a solid choice for most locations. And in more moderate climates, the difference in performance will be negligible. I don’t live in an extremely hot climate, so I rarely see a significant hit to my system’s performance due to excessive heat.

It’s also important to consider that SunPower panels start at a higher efficiency (22.35% on average) than most other brands. So even when they lose a bit more power in high temperatures, they may still be producing more electricity overall than lower-efficiency panels with better temperature coefficients. 

The bottom line is that SunPower panels will perform well in the vast majority of locations and climates. While they may not be the absolute best choice in the hottest areas, their temperature coefficient is better than the industry standard. Plus, their high efficiency means they can still deliver top-tier performance even if they underperform slightly on the hottest days.

SunPower Panels Sustainability

1.88/2.5

Most people see solar energy as a reliable source of clean energy that helps reduce our reliance on fossil fuels and fight climate change. While that’s true, there are some caveats.

For starters, the solar industry isn’t entirely harm-free when it comes to environmental impact. Manufacturing solar panels requires mining raw materials, such as quartz for silicon cells, and the process of transforming those materials into solar cells is energy intensive. Most of that energy currently comes from burning fossil fuels, especially in countries with less-strict environmental regulations.

Additionally, solar panels contain some toxic materials, such as lead, that can harm the environment if panels are not properly disposed of at the end of their lives. As solar continues to grow, it’s crucial that manufacturers focus on sustainable practices to minimize these negative effects.

SunPower leads by example, which is why it scores 1.88 out of 2.5 for sustainability. Here are some of the key factors that influenced my scoring:

• Recycled materials: SunPower uses recycled content in its panels, which helps reduce the demand for raw materials and the emissions associated with mining and processing them. While the company doesn’t disclose exactly what percentage of its panels are made up of recycled content, using any recycled materials at all is a step in the right direction and earns SunPower 2,5 points in this category. Companies that don’t use recycled materials earn zero points.
• End-of-life recycling: SunPower also has an end-of-life (EoL) recycling program for its panels, which ensures that the materials in old panels can be reused to make new panels instead of winding up in a landfill. This is important for preventing toxic panel components — like the lead I mentioned before — from leaching into the environment. It also reduces the need for new raw materials, which indirectly improves the solar industry’s sustainability by reducing the need to mine quartz and metals. SunPower’s end-of-life program adds another 2.5 points to its score.
• Manufacturing location: While SunPower is an American company, its panels are manufactured by its sister company Maxeon in Malaysia and the Philippines. Producing panels outside of the United States means SunPower forgoes 2.5 points, as it’s more difficult to enforce strict environmental standards overseas.
• Lack of moral issues: My research didn’t uncover any history of moral issues like forced labor, discrimination or worker exploitation tied to SunPower or Maxeon. Unfortunately, the solar industry has a history of manufacturers exploiting their labor forces to reduce the cost of making solar panels. The absence of these serious ethical breaches earns the company another 2.5 points.

It’s important to note that even solar panels produced with little recycled content and no end-of-life recycling program are still far better for the planet than fossil fuels. The emissions and environmental damage from manufacturing solar panels pale in comparison to the harm caused by extracting and burning coal, oil and gas, which the panels will serve to offset after installation.

The half a million solar panels that SunPower has installed across the United States have dramatically reduced the country’s carbon emissions, and they’ll continue to generate clean electricity for 25 years or more.

With that said, as the solar industry continues to grow rapidly to meet the urgent need for clean energy, it’s critical that companies prioritize sustainability to reduce the technology’s negative impacts as much as possible. SunPower’s use of recycled materials, end-of-life recycling program and lack of moral scandals make it one of the more sustainable solar manufacturers today. The fact that it has upheld those standards over its nearly 40 years makes the company one you can support without guilt.

SunPower Panels Appearance

2.5/2.5

I believe that function trumps form when it comes to solar panels, but there’s no denying that some panels simply look better than others. How much you value your solar panels’ appearance — if you value it at all — is entirely personal preference. What you prefer might also not be the same as what I prefer, but there are some trends in taste that have emerged as more people make the switch to solar. Try not to take this aspect too seriously, though, as it’s highly subjective.

In my opinion, SunPower makes some of the sleekest and most attractive solar panels on the market, which is why I give it 2.5 out of 2.5 for Appearance. I could end this portion of the article here and move on, but I won’t. Let me explain my reasoning.

In general, people — me included — prefer panels that don’t stick out like a sore thumb on their roofs. That usually means darker colors that don’t show any surface details. SunPower’s Maxeon panels use all-black monocrystalline panels. They stick out less on a roof with dark-colored shingles than the older, less efficient, blue-tinted polycrystalline panels.

SunPower’s panels also lack grid lines. Some panels have visible lines that make a rectangular grid pattern on the panel’s surface. While these grid lines are essential for photovoltaic cells to function, how prominent they are has a major impact on the way solar panels look. I prefer my grid lines to be as faint as possible. Maxeon panels don’t have visible grid lines, which didn’t factor into my decision to go with SunPower but does make my system look sleeker and more modern, and most homeowners prefer this appearance overall.

There’s not much more to say here. If you’re like me and most other solar customers and like the black, gridless panel look, all of SunPower’s panels will fit your aesthetic perfectly.

SunPower Panels Comparison

Here’s a table that compares SunPower’s ratings with two other similar-sized solar panel manufacturers.

Does SunPower Make Any Other Solar Products?

SunPower’s Maxeon panels are its main product, but the company also makes solar batteries called the SunVault. These batteries come in a variety of sizes that range from 13 kW up to 52 kW. For residential use, most homes need around 26 kW to run essential systems for two weeks in the event of a power outage, based on our research. That means one 26-kW SunVault system or two 13-kW systems should be sufficient. SunPower also offers a middle-ground option with 19.5 kW of storage in case your electricity needs fall somewhere in between.

Unfortunately, SunPower doesn’t make its own electric vehicle (EV) charging station, so you’ll have to install one from another manufacturer if you want to charge an EV at home. Most SunPower installers do offer the WallBox Pulsar EV charger.

All SunPower systems include system monitoring via the mySunPower app. The app lets you see your system’s energy production and change the storage preferences for your batteries if you have any. System monitoring is a standard feature that most solar companies offer and usually doesn’t cost anything extra.

Who Are SunPower’s Panels Best For?

SunPower’s panels are best for people who don’t mind paying top dollar for a premium product. SunPower’s Maxeon panels are still among the most efficient available for residential customers, although the gap between SunPower and competitors like REC, LONGi and Canadian Solar has narrowed in recent years.

SunPower is also a great option if you value peace of mind. The premium you pay for a SunPower solar system also gets you the best warranty coverage in the entire solar industry. SunPower’s equipment warranty covers your entire system — your panels, inverters, wiring and mounting racks — for 40 years. The company’s performance guarantee is also the best in the business. SunPower’s efficiency warranty guarantees that your system will maintain at least 98% of its initial power output after the first year, 92% after 25 years and 87% after 40 years. Those performance guarantees are the best I’ve seen, and no other company comes particularly close.

The toughest pill to swallow with SunPower is its cost. If you’re on a tight budget, SunPower panels are pretty much out of the question for you. You can spend between 10% and 20% less and get a solar panel system with REC or Q Cells panels and sacrifice only a few percentage points of efficiency. Those companies only offer 25-year warranties, but that’s still long enough to get you through most of your system’s useful lifespan — and secure an average of over $31,000 in net savings, based on our research — worry-free.

What’s Next? 

If you’re sold on the benefits of SunPower panels, you should check out our overall review of SunPower, which covers the company’s reputation, services and financing options in more detail. You should also make an appointment with your local SunPower dealer for a free quote visit. SunPower dealers don’t charge you for an initial consultation, so you can hear what the company has to say without any strings attached. You can also use our solar panel cost guide to get a rough idea of what your system should total.

On the other hand, if you don’t think SunPower panels are a good fit for your home, you should read some of our other panel reviews. We have a Q Cells panel review that is worth reading if you’re looking for a more budget-friendly panel option. Q Cells panels are extremely popular because they’re reasonably efficient and durable, but they cost less than Maxeon panels.

You can also check out our solar savings calculator to see how much you could save by switching to solar. It uses your home’s location and energy usage to calculate a more accurate estimate of your potential savings than the overall U.S. averages I quoted in this article.