Solar Panel Looks Cloudy or Bubbling? It Could Be Delamination

  • Post last modified:March 30, 2026

Solar Panel Looks Cloudy or Bubbling? It Could Be Delamination

Solar energy systems are designed to be “set it and forget it” investments, often carrying warranties that span 25 years or more. However, as these systems age or face extreme environmental conditions, physical changes can occur within the modules. If you have noticed that your solar panel looks cloudy, has mysterious bubbles under the glass, or shows signs of browning, you are likely witnessing a phenomenon known as delamination. This is more than just an aesthetic flaw; it is a significant structural failure that can compromise the efficiency and safety of your entire solar array.

In this comprehensive guide, we will explore what solar panel delamination is, why it happens, how to identify it early, and the critical role that advanced adhesives and encapsulants play in preventing these failures. Understanding the root causes of delamination is essential for homeowners, commercial installers, and manufacturers alike.

What Exactly is Solar Panel Delamination?

To understand delamination, we first need to look at how a solar panel is constructed. A standard crystalline silicon solar panel is a “sandwich” of several layers, bonded together under heat and pressure through a process called lamination. These layers typically include:

  • Tempered Glass: The top layer that protects the cells from the elements.
  • Encapsulant (usually EVA): A clear, adhesive-like layer (Ethylene Vinyl Acetate) that surrounds the solar cells, protecting them from moisture and mechanical stress.
  • Solar Cells: The silicon wafers that convert sunlight into electricity.
  • Backsheet: A polymer layer on the bottom that provides electrical insulation and additional moisture protection.
  • Frame: Usually aluminum, which holds the assembly together.

Delamination occurs when the bond between these layers—most commonly between the glass and the encapsulant or the encapsulant and the cells—begins to fail. When the adhesive bond breaks, gaps are created. These gaps allow air and moisture to enter the internal circuitry of the panel, leading to the “cloudy” or “bubbling” appearance that many owners report.

Common Signs: How to Spot Delamination

Identifying delamination early can save you from a total system failure. While some changes in appearance are normal over decades of sun exposure, the following signs are red flags that the structural integrity of your panels is failing.

1. Cloudiness or Milky Patches

One of the first signs of delamination is a foggy or milky appearance underneath the glass. This often looks like condensation that won’t go away. This cloudiness is typically caused by moisture ingress or a chemical reaction within the EVA encapsulant. As the bond weakens, water vapor enters and reacts with the materials, creating a hazy film that blocks sunlight from reaching the solar cells.

2. Bubbles and Blisters

If you see small or large bubbles trapped beneath the glass, the lamination has failed. These bubbles are often filled with air or gases released during the degradation of the adhesive layers. Bubbling is particularly dangerous because it creates a pocket where heat can build up, potentially leading to hotspots that can crack the glass or melt the backsheet.

3. Browning or Discoloration

While browning (often called “snail trails” or “EVA browning”) can be a separate issue related to the chemical breakdown of the encapsulant, it is frequently a precursor to or a result of delamination. When the EVA layer degrades due to UV exposure and high temperatures, it releases acetic acid. This acid further weakens the bond between layers, accelerating the delamination process and corroding the metal grid lines on the solar cells.

4. Lifting of the Backsheet

Delamination isn’t always visible from the front. If you inspect the back of your panels and notice the white or black plastic sheet peeling away or showing ripples, the rear lamination is failing. This exposes the electrical components to the elements and creates a significant shock hazard.

The Root Causes: Why Do Solar Panels Delaminate?

Delamination is rarely the result of a single factor. Usually, it is a combination of environmental stress and manufacturing quality. Here are the primary drivers of this issue:

Moisture Ingress

Moisture is the number one enemy of solar panels. If the edge seals of the panel are not perfectly airtight, or if the adhesive used in the lamination process is of poor quality, water vapor will eventually find its way in. Once moisture is inside, it acts as a catalyst for chemical degradation and physical separation of the layers.

Thermal Cycling

Solar panels live in a harsh environment. They heat up under the midday sun (often reaching temperatures above 65°C/150°F) and cool down rapidly at night or during rainstorms. This constant expansion and contraction is known as thermal cycling. If the adhesives used to bond the glass, cells, and backsheet do not have the necessary flexibility or “peel strength,” the physical stress of thermal cycling will eventually pull the layers apart.

Poor Manufacturing Quality

In the race to lower the cost of solar energy, some manufacturers may use inferior encapsulants or cut corners during the lamination process. If the panels are not “cured” for the correct amount of time or at the right temperature, the cross-linking of the EVA polymer will be incomplete. This results in a weak bond that is highly susceptible to failure within just a few years of installation.

UV Radiation

Ironically, the very thing solar panels need to function—sunlight—is also a primary cause of their degradation. High-intensity UV radiation breaks down the molecular bonds in lower-quality plastics and adhesives. Over time, this UV degradation makes the encapsulant brittle, leading to cracks and eventual delamination.

The Consequences of Ignoring Delamination

Many people assume that if a panel still looks mostly okay and is producing some power, the cloudiness or bubbles are just cosmetic. This is a dangerous misconception. Delamination leads to several serious problems:

Significant Power Loss

Cloudiness blocks and scatters sunlight, meaning fewer photons reach the silicon cells. Furthermore, as moisture enters the panel, it causes corrosion on the silver busbars and fingers that collect electricity. This increases internal resistance, drastically reducing the panel’s wattage output. A delaminated panel can easily lose 20% to 50% of its rated power in a short period.

Hotspots and Fire Risks

When a portion of a panel delaminates, it creates uneven electrical resistance. This causes certain cells to work harder than others, creating “hotspots.” These areas can become hot enough to melt the plastic backsheet or even cause the tempered glass to shatter. In extreme cases, hotspots have been known to start roof fires.

Safety and Electrical Shocks

The backsheet and encapsulant serve as electrical insulators. When these layers delaminate and moisture enters, the panel’s insulation resistance (Riso) drops. This can lead to “ground faults,” where electricity leaks from the panel into the mounting rack or the roof. This is not only a fire hazard but also a significant shock risk for anyone performing maintenance on the system.

Can Delaminated Solar Panels Be Repaired?

The short answer is: generally, no. Because solar panels are vacuum-sealed and thermally bonded units, there is no easy way to “re-glue” the layers once they have separated. Injecting adhesives into the bubbles or trying to reseal the edges is usually a temporary fix that does not address the internal corrosion already taking place.

If your panels are showing signs of delamination, your best course of action is to:

  • Check Your Warranty: Most reputable manufacturers provide a 10 to 25-year warranty against manufacturing defects, which includes delamination.
  • Contact Your Installer: Have a professional perform a “megger test” to check the insulation resistance and a thermal imaging scan to identify hotspots.
  • Replacement: In most cases, the affected panels will need to be replaced to ensure the safety and performance of the overall system.

The Importance of High-Quality Adhesives and Encapsulants

The prevention of delamination starts at the manufacturing level. The longevity of a solar panel is almost entirely dependent on the quality of the chemicals used to bond it together. This is where advanced material science becomes critical.

Industrial-grade adhesives and UV-curable resins are the unsung heroes of the solar industry. To prevent delamination, these materials must possess:

  • High Peel Strength: The ability to maintain a bond under extreme mechanical stress.
  • Excellent Moisture Barrier Properties: Preventing water vapor from reaching the cells.
  • UV Stability: Resisting the breakdown caused by decades of sun exposure.
  • Thermal Flexibility: Moving with the panel as it expands and contracts, without cracking or peeling.

For manufacturers looking to improve the reliability of their modules, choosing the right bonding solutions is paramount. Using high-performance sealants for junction boxes and edge sealing can provide that extra layer of protection that prevents moisture ingress from starting the delamination process in the first place.

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How to Prevent Delamination During Installation and Maintenance

While homeowners can’t control the manufacturing process, there are steps that can be taken during installation and maintenance to minimize the risk of delamination:

1. Ensure Proper Ventilation

Solar panels should be installed with a sufficient gap between the panels and the roof. This allows for airflow, which helps keep the panels cooler. Excessive heat accelerates the chemical breakdown of the EVA layer, so keeping temperatures down can extend the life of the lamination.

2. Avoid Abrasive Cleaning

Using harsh chemicals or high-pressure washers can damage the edge seals of the panels. Once an edge seal is compromised, moisture ingress is inevitable. Clean your panels with nothing more than water and a soft brush or squeegee.

3. Regular Visual Inspections

At least once a year, take a close look at your panels (using binoculars if they are on a high roof). Look for the milky spots, bubbles, or browning mentioned earlier. Catching these issues while the panels are still under warranty can save you thousands of dollars in replacement costs.

4. Choose Quality Over Price

When purchasing a solar system, the cheapest panels are often the ones most susceptible to delamination. Look for Tier 1 manufacturers who have a proven track record of durability and use high-quality encapsulants and backsheets. Researching the “Bill of Materials” (BOM) for a panel can sometimes reveal if they use premium components like DuPont Tedlar backsheets or high-grade adhesives.

Conclusion

Solar panel delamination is a serious issue that transforms a high-performing green energy asset into a potential liability. Whether it manifests as a cloudy haze, unsightly bubbles, or brown discoloration, the underlying cause is a failure of the internal bonds that hold the panel together. Driven by moisture, heat, and UV exposure, delamination reduces efficiency and poses real safety risks.

As the solar industry continues to mature, the focus is shifting from simply lowering costs to ensuring long-term reliability. This reliability is built on the foundation of superior chemistry—specifically, the adhesives and encapsulants that protect the sensitive silicon cells from the world’s harshest environments. By choosing high-quality components and performing regular maintenance, we can ensure that solar arrays reach their full 25-year potential.

If you’ve noticed your solar panel looks cloudy or bubbling, don’t wait for the system to fail completely. Consult with a professional, check your warranty, and ensure your next set of panels is built with the high-performance materials necessary to withstand the test of time.

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