How Long Solar Panels Last (Long-term Investment)

If you’re looking for ways to reduce your carbon footprint while saving some money, solar panels are an excellent investment. While they require a sizable upfront cost, solar panels can contribute to significant savings over time.

Before investing in residential or commercial solar panels, it’s important to know how long they can last. In this article, we’ll be taking a look at solar panel longevity, as well as other factors, including:

Solar panel degradation
Factors that impact solar panel longevity
What happens when solar panels degrade
Solar panel maintenance
Replacing solar panel components
How long it takes for solar panels to pay for themselves

Let’s find out how much bang for your buck you can get from high-quality solar panels.

How Long Do Solar Panels Last?

High-quality solar panels typically have a production lifespan of between 25 and 30 years.

However, solar panels don’t necessarily break down or cease to produce electricity at this point. They begin to experience degradation, which essentially means their solar output is reduced.

We will discuss the process of degradation and its effects on solar panels later on.

Apart from physical damage due to a storm or accident, degradation has the most significant impact on how long solar panels last. Depending on the climate and panel positioning, degradation can occur at different rates. Solar panels continue to produce electricity until degradation has rendered them obsolete.

However, the point at which they are no longer economically beneficial is usually around the 25 or 30-year mark.

How Long Do Solar Panels Last On a House?

Solar panels, whether used for residential or commercial properties, generally have the same lifespan of 25 to 30 years.

Although commercial panels are a little bigger and maybe more efficient, they are expected to have a similar production life as those you would install on your home.

How Long Do Solar Panels Last UK?

When all conditions are equal, solar panels in the UK last the same length of time as those in other regions: 25 to 30 years.

However, certain factors, such as the UK weather, can impact this lifespan.

For example, panels can be damaged from storms, hail, or loose debris. As the UK experiences more rain and hail than in other parts of the world, the risk of damage may be higher.

How Long Do Solar Panels Last Without Sunlight?

In a total absence of light and the right storage conditions, solar panels may not experience any degradation.

Typically, the panels start to degrade once the installation process begins and they are exposed to light. However, weather, dust, debris, and temperature fluctuations can damage a panel so the storage conditions must be optimal.

In terms of electricity generation, solar panels require at least some light source. However, this doesn’t mean they need direct sunlight. Commercial solar panels generate electricity using photons from all-natural light. This means they can function on cloudy days or in positions where they aren’t in the direct paths of the sun’s rays.

As long as solar panels are in use, they experience degradation. Therefore, they have an expected lifespan of 25 to 30 years, regardless of their position or light exposure.

Solar Panel Degradation

Degradation can be defined as the reduction in the output of solar panels over time. It is perhaps the most important factor in determining how long panels last. According to the NREL, solar panels degrade at a rate of approximately 0.5% per year (average). This means that after 20 years of use, solar panels only operate at 90%.

Most solar panel manufacturers base their product warranties on this timeframe. They generally offer protection on their products for up to 25 years or more. Some newer, higher-powered solar panels may even come with a 30-year warranty.

Why Do Solar Panels Degrade?

Solar panels degrade for several reasons, including the quality of the panel, product assembly, installation, maintenance, and weather conditions.

Degradation is generally triggered by light exposure or aging.

Light Degradation

Chemical breakdowns from light exposure occur within the panels in several different ways:

Light-Induced Degradation (LID): this is where the panel’s crystalline silicon cells are exposed to the outside environment, like sunlight, wind, rain, or temperature fluctuations.
Direct Light-Induced Degradation (DLID): extensive exposure to direct sunlight can damage the electronics within photovoltaic cells.
Ultra Violet Light-Induced Degradation (UVID): exposure to direct sunlight leads to the silicon oxide on the surface of a solar panel to develop a substance called boron dioxide, which lowers the panel’s efficiency.

Age-Based Degradation

Unless solar panels are stored in optimal conditions such as a temperature-controlled laboratory, they inherently degrade over time. Natural elements that can damage panels include:

Rainfall
Snow
Ice
Heat
Cold
Dust
Sand

Exposure to such materials can cause microcracks on the surface of the panel, damaging the protective seal. Once the seal is compromised, water and other forms of debris can infiltrate the panel, damaging the electronics. If this happens, the panel can break down very quickly.

If the panel experiences damage due to natural degradation, you’re likely to see a significant dip in productivity within a short period.

Solar Panel Quality

Simply put, high-quality materials contribute to longer-lasting solar panels.

The quality of components may raise the price of a solar panel but it can also make it more resilient and reduce the rate of degradation. Some of the most important materials include:

Solar glass
Aluminum frame
Solar cells

Cheaper solar panels are often built with thin frames that contain lower levels of aluminum. This reduces their structural integrity and makes them more susceptible to damage.

Assembly

Assembling panels is a complex process that requires precision wiring and soldering. Poorly assembled panels or errors in manufacturing can accelerate degradation, particularly if it affects the oxidation levels or causes a voltage leak.

Installation

Damage can easily occur during the installation process. Mishandling the panels can cause micro-cracks or scratches to the surface, diminishing performance and speeding up degradation. Poor installation techniques may also lead to badly fitted electrical wiring which can greatly reduce performance.

Another crucial aspect of the installation process is positioning. The panels must be placed at the most appropriate angle to not only garner the lightest exposure but also to create the most optimal position for self-cleaning functions and mechanical resistance.

Maintenance

Solar panels don’t require a lot of maintenance.

However, you should always make sure to keep an eye on their condition to ensure there isn’t a build-up of dust, debris, or potentially harmful substances. The most important components to monitor include the cables, inverters, and connections.

Weather

Solar panel degradation can be accelerated by various types of weather events such as heatwaves, storms, snow, and torrential rain. Temperature fluctuations may also cause the inner components to expand and contract, leading to damage. Extreme temperature changes are most harmful.

What Happens To Solar Panels After 25 Years?

After 25 years of use, solar panels degrade to the point where they are no longer economically beneficial.

It’s important to note that solar panels continue to produce electricity after 25 years. However, their energy production no longer meets efficiency levels that are optimal for a building’s energy needs.

Fortunately, the savings you can make throughout a panel’s useful life should be enough to more than pay for the system.

Interestingly, a recent study from the Joule journal, reported that panels with lifetimes of 10 years can be economically viable. What’s more, they may even suit grid-scale applications. According to the study:

“PV technologies are improving rapidly along several dimensions, including cost, power conversion efficiency, and reliability. Periodic module replacement or planned repowering takes advantage of this technological improvement and counteracts predictable degradation. “
Michael Woodhouse and Vladimir Bulovic, 2019

Solar Panel Degradation Rate Comparison

Solar panels have a degradation rate of approximately 1% per year. Depending on the quality of materials, these figures can vary slightly. Tier 1 panels tend to last the longest due to the high-grade materials used to manufacture them.

Most manufacturers place guarantees on their units that are intended to last as long as the useful lifespan of the panels. The industry standard indicates that panels will maintain 90% of their production value for the first ten years and approximately 80% after 25 to 30 years.

The following table compares solar panel degradation between tier 1, 2, and 3 panels.

Panel Tier	Degradation	Output Reduction Over 25 Years	Remaining Output After 25 Years
Tier 1	0.3%	6.96%	93.04%
Tier 2	0.5%	11.33%	88.67%
Tier 3	0.8%	17.53%	82.47%

Do Solar Panels Need A Lot Of Maintenance?

Another great benefit of solar panels is that they generally require very little maintenance.

The only difficult part is accessing your panels. If they’re located on your roof, be sure to take every precaution to stay safe, or hire a professional cleaning service.

The most important maintenance for solar panels is to keep them free from debris. Solar panels are usually positioned at an angle so rain and wind are natural cleaners. If you live in a dusty, sandy, or smog-heavy region, watch out for a build-up of sediment on your panels. This can negatively impact their energy output.

To clean, simply rinse the panels with clean water. Although you can use mild detergent and soap, avoid using abrasive substances. These may scratch or damage the panels, reducing their efficiency. There is no set number of times you should clean your panels. In general, somewhere between 2 and 5 times per year should be adequate.

It’s important to track the productivity and efficiency of your panels to make sure they are performing adequately. A dip in efficiency could indicate an issue.

Do Solar Panels Break Easily?

Solar panels are quite durable and don’t break easily.

The glass that covers the exterior of each unit is designed to stand up to severe weather conditions and impact from debris. The quality of the components and materials used to make each unit determines how durable it is. The higher the quality of the component, the stronger it is likely to be.

By checking on the condition of your panels regularly, you can avoid most major problems. Serious issues tend to occur if the damage goes unnoticed. Over time, the compromised component can deteriorate, leading to further damage. If the solar cell eventually becomes exposed, the unit is likely to break.

What Contributes to Solar Panel Durability?

Some of the most important components that contribute to solar panel durability include:

Solar Cells

Solar manufacturers are rated by independent analysts in the PV industry. Tier 1 panels are the highest grade units on the market. Where possible, customers should always purchase from a tier 1 manufacturer to ensure they have the highest quality cells.

Tier 1 manufacturers typically control all aspects of cell production. They often invest significantly in research and development (R & D). This results in the widespread use of automated manufacturing processes, leading to high-quality and reliable products.

Tier 2 and 3 manufacturers are much smaller operations. They generally don’t have R & D teams and are much newer to the business. While there are some high-quality and cost-effective solar options from tier 2 manufacturers, they come with a risk.

Glass

The type of glass affects the performance of solar panels in several ways. Firstly, low-quality glass can break easily, exposing the inner components of a panel to the elements. Even minor cracks can allow moisture to slip through, reducing efficiency. Over time, the poor-quality glass may become clouded, blocking the light, and further reducing panel performance.

Tempered glass is the preferred type in the industry. It is highly durable and resistant to clouding, making it an excellent option for all solar panels.

Edge Seal

High-quality materials must be secured with strong seals to prevent moisture or other materials from penetrating the exterior. Silicon-based sealants are the industry standard. Manufacturers and repair technicians should use silicon-based sealants for securing or resealing frames and junction boxes.

Back sheet

The panel back sheet is a key component that contributes to safety and efficiency. If the back sheet is compromised, the unit can experience power loss and degradation. Solar customers should avoid panels built from non-UV resistant polyvinylidene difluoride (PVDF). Opt for back sheets manufactured from UV-blocking polyvinyl fluoride (PVF) film.

Junction Box

The junction box is located at the rear of the panel. It contains the electronic connections for the PV strings as well as the output interface for the panels. Any moisture penetration could cause severe damage to the modules. The junction box should have a silicon cover and be secured with a durable sealant.

Connectors

Most modern solar panels use MC4 connectors. They are high in quality and make the wiring process quick and easy.

Inverter

The PV inverter converts the DC output from the panel into usable energy (AC current). This energy can then be hooked up to a commercial or off-grid electric network.

Racking

Solar racking holds an entire system in place. As panels are often placed at angles on elevated platforms or roofs, racking must be durable and secure. Typically, the most stable racking is made from aluminum. It is very strong and lightweight when compared to alternative materials.

Why Do Solar Panels Stop Working?

While degradation occurs naturally, it is often accelerated due to damage or over-exposure to the elements.

Thermal cycling, humidity, extended UV ray exposure, and heat can cause sealants to fail or panels to crack. If this type of damage goes unnoticed, a solar system is likely to fail before long.

How Often Do Solar Panels Need To Be Replaced?

Good solar panels can last anywhere from 20 to 30 years, but there’s not necessarily a specific time you should replace yours.

It’s more important to pay attention to their productivity.

If your solar panels are still in good shape and producing enough electricity, then they may not need to be replaced. On the other hand, if you find that your electricity bill is going up because your solar panels are no longer doing the trick, then it’s probably time to replace them.

Can Solar Panels Last 40 Years?

In theory, solar panels can remain operational after 40 years.

However, due to degradation, they are most likely to be past their “useful” lifespan. A 40-year-old solar panel is highly unlikely to contribute to an efficient electrical system.

One of the key advantages of solar panel systems is that many of the components can be repurposed. 95% of the panel glass, 85% of the silicon, and much of the aluminum frame may be recycled and used to create even more solar products.

How Long Does It Take For Solar Panels To Pay For Themselves?

It takes US-based homeowners around 8 years to recoup their solar panel investment in savings.

Depending on the location, positioning of the panels, and quality of materials, this figure can deviate slightly. You have to remember that solar panels not only save you money on your monthly bills, but they also contribute to savings via rebates and federal solar investment tax credits.

How Much Does It Cost To Replace A Solar Panel?

Replacing an entire solar panel costs around $12,000 on average (after federal tax incentives).

However, more comprehensive, Tier 1 systems can cost $40,000 or more to install.

Sources