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What you should know about solar panels efficiency over time

Solar panels have emerged as a prominent solution for harnessing clean and renewable energy from the sun. As the world embraces sustainable practices, understanding the efficiency of solar panels over time becomes crucial.

Solar panel efficiency refers to their ability to convert sunlight into usable electricity. While solar panels are known for their durability, it is essential to recognize that their efficiency can change gradually over the years.

In this article, we will explore the factors that influence solar panel efficiency over time, including degradation, technological advancements, maintenance practices, and warranties.

Solar panel efficiency over time

Solar panel efficiency is an important factor to consider when evaluating their performance and determining their long-term viability. Here are some key points about solar panel efficiency over time.

Solar panel initial efficiency

When solar panels are manufactured, they have a specific efficiency rating that indicates the percentage of sunlight they can convert into electricity. The efficiency of commercially available solar panels can vary but typically ranges from 15% to 22%.

Solar panel degradation

Over time, solar panels experience a gradual decrease in efficiency, primarily due to a process called panel degradation. This degradation is mainly caused by factors such as exposure to sunlight, temperature fluctuations, humidity, and other environmental conditions. However, modern solar panels are designed to minimize degradation and have improved durability.

Solar panel manufacturers typically provide a degradation rate in their product specifications, indicating how much efficiency loss can be expected over time. The most common degradation rate is around 0.5% to 1% per year. Therefore, a solar panel with an initial efficiency of 20% might have an efficiency of around 80-90% after 25 years of operation.

solar panels efficiency over time

Technology behind solar panel modules

Solar panel technology has been steadily advancing, and newer models often offer higher efficiencies compared to older ones. As research and development continue, more efficient materials and manufacturing processes are being introduced, which can lead to higher overall efficiency and improved performance.

Maintenance and Cleaning

Proper maintenance and regular cleaning of solar panels can help maintain their efficiency over time. Dust, dirt, leaves, or other debris that accumulate on the panel’s surface can reduce sunlight absorption and hinder the energy conversion process. Regular inspections, cleaning, and maintenance can help ensure optimal performance.

Warranties and upgrade options

Solar panel manufacturers typically provide warranties that guarantee a minimum level of performance over a specified period. These warranties often cover both product defects and performance degradation. When considering solar panels, it’s essential to review the warranty terms to understand the manufacturer’s commitments regarding efficiency.

If the efficiency of older solar panels becomes significantly lower than desired or if newer, more efficient models become available, it may be possible to upgrade or replace the existing panels. However, this depends on the specific installation and compatibility with the current system.


While solar panels do experience a gradual decrease in efficiency over time, proper maintenance and advancements in technology can help mitigate the effects of degradation.

When evaluating solar panel options, it is crucial to consider both the initial efficiency and the expected degradation rate to make proper decisions about long term solar panel performance.