Used solar panels: Are they a good idea?

It’s hard to argue with the benefits of going solar: saving money while reducing your environmental impact is a win-win. But the up-front costs associated with installing a new solar system are intimidating, and you may be looking to trim your initial expenses by shopping for used solar panels. 

In this article, we’ll compare the pros and cons of used vs. new solar panels. While we at EnergySage don’t think used panels are a good idea for most homeowners interested in rooftop solar, we’ll help you decide whether they might be right for your project.

There is tremendous variety in the used solar panel market. At one end, you have individuals selling off decades-old panels from aging residential systems, while at the other end you’ll find installers looking to clear out excess, never-used panels to make space for new inventory. You’ll also see refurbished panels for sale. Often when commercial or utility solar farms update their equipment, refurbishers will thoroughly test the used panels and repair or replace internal components prone to wearing out, like cables and connectors, before reselling them.

The biggest factor to consider is the need to evaluate, inspect, and consider each used panel needed for your project. When installing new solar panels, the installer will work with you to select the right panels for your needs, they will check for defects, and they will ensure each panel is uniform. 

When shopping for used panels, you’re on your own, and you’ll need to independently evaluate each panel’s condition and suitability for your project. You need to take into consideration wattage and efficiency rating, age, degradation, condition, and whether they’re still covered by a warranty.

Wattage and efficiency rating

As we cover in another guide, solar panels are rated according to how much power in watts they can produce, or their wattage, as well as how efficiently they can convert sunlight to electricity. In the last decade, solar panel technology has improved considerably, and newer, higher-efficiency panels can produce more power per square foot than older, less-efficient panels.

Just five years ago, the average solar panel efficiency in quotes through EnergySage was 19%. In 2024, the average efficiency is about 21.4%, which translates to 10% more electricity produced per panel. 

Depending on your power needs, sun exposure, and space constraints, you may not need the newest, most efficient panels, but you should still consider the fixed costs associated with mounting and wiring each additional panel. 

Age and degradation

While considering the wattage and efficiency of used panels is a good starting point, don’t expect them to perform to the stated levels. As solar panels age, their performance degrades, and they produce less power than when they were brand new.

The National Renewable Energy Laboratory estimates that the median rate of degradation is about .5% per year, but recent research suggests that the decline isn’t linear, and that degradation may accelerate around 20 years during what researchers call the “wear-out phase.”

What does this mean for you?

While a new solar system will have a lifespan of about 25 years before you experience a meaningful dip in production, used panels will start out less efficient and will reach the wear-out phase sooner.  

Condition

Damaged and flawed panels are common on the used solar market. While some kinds of flaws, like blemishes, will impact performance, other kinds of damage can simply be dangerous, placing your home and electrical system at risk. So knowing what to look for when inspecting used panels is very important. Here is a good visual guide to common panel blemishes and associated performance considerations. 

The major damage to avoid is cracked or broken glass. Cracks might allow water to leak into the panel, affecting the electrical components and increasing the risk of fire and electrocution. 

Warranty

Going solar is an investment in your future, and almost all solar panel manufacturers offer warranties for their panels to help protect your investment. As we cover in another article, most quality manufacturers protect their panels for 25 years and guarantee they’ll still produce nearly 90% of the original power output at the end of that period.

Some large re-sellers offer 1-year warranties on their used panels, but most used panels from individual re-sellers do not come with any warranty. If the panel doesn’t work, fails, or the performance significantly degrades, you’re usually out of luck.

Connecting to the grid

Used panels are good options for off-grid systems, but they can pose a challenge if you’re trying to connect to the grid. Your utility will require a certified electrician to sign-off on your solar system and ensure that it is up to code before allowing you to tie into the grid. Among other things, they’ll need to ensure that your panels are UL-listed by looking for the appropriate manufacturer’s labels. If these labels have been removed, as they often are on used panels, then they won’t pass inspection and you won’t be able to connect your system to the grid.

Undoubtedly, price is the major appeal of used panels. On average, you can find used panels for between $0.05 and $0.60 per watt, according to experts on the secondary solar market. By comparison, according to recent data from the EnergySage marketplace, the cost-per-watt for new panels averages around $2.75/W before incentives.

To compare the price of new vs. used, you’ll have to weigh other factors like available credits and incentives. New panels are likely to qualify for a 30% federal solar tax credit and may qualify for further state and local incentives. Per the Department of Energy, panels must be “new or being used for the first time” to qualify for the 30% federal solar tax credit, so used panels won’t do you any favors come tax time.

While buying used panels represents a major immediate savings compared to buying new, the short-term value may not be worth it, in our opinion. New panels are more efficient with longer useful lifespans and warranties to back up their performance. Current market conditions also make this a relatively good time to buy new. The cost of new panels is currently near an all-time low, where industry experts predict prices to remain into 2025.

Because you can expect higher efficiency for a longer period with new solar panels, we think they’re the better long-term choice for most homeowners looking for rooftop solar. They’ll power your home for years to come, maximize available sunny roof real estate, and you won’t be climbing up in a few years to replace them. A professional installer will also ensure that your panels are up to code and properly permitted so you can tie into the grid. And they’ll be protected for years to come by warranties. 

However, there are a number of smaller-scale, off-grid DIY projects where used solar panels can make a lot of sense. If you’re looking to power a cabin, tiny home, shed, etc., or just keep a small battery charged, used panels can save you significant money up-front.

In general, smaller off-grid projects where you can tolerate lower efficiency panels (i.e. lots of space for panels or low electric usage) are good candidates for used solar panels.

If you're looking to shop for used solar panels, re-sale marketplaces such as Craigslist, Facebook Marketplace, and eBay are good places to start. If you’ve ever shopped these sites before, though, you know that spotting a good deal requires patience and careful scrutiny to identify trustworthy sellers.

Look for high-rated sellers with a record of positive feedback from buyers, thorough descriptions of the panels and their present condition, and clear, well-lit photos. Be cautious when dealing with new or poorly-reviewed sellers, listings with only stock images, or listings where the descriptions do not match the photos.

Another option is ordering from a reputable solar panel re-seller, like SanTan Solar, that thoroughly tests and inspects used panels and includes a standard 1-year warranty. Unless you’re local to a SanTan Solar warehouse, however, you’ll want to factor in the cost of shipping.

So you do have options to find used solar panels, but it’s important to not quickly jump into a purchase.