How Summer Heat Affects Your Solar Panels: Efficiency Loss & Solutions

Solar panel efficiency decreases as temperatures rise. For every degree Celsius above the standard test temperature (25°C), a panel’s power output can drop by approximately 0.3% to 0.5%, a key metric known as the temperature coefficient.

How High Temperatures Impact Your System

The main challenge of summer is the balance between abundant sunlight and rising panel heat.

Long-Term Stress: Consistent exposure to high heat can accelerate the very slow, natural aging process of the panel’s encapsulation materials over many years.

Reduced Energy Production: On extremely hot days, panel temperatures can exceed 65°C, leading to measurable efficiency losses. While you get more sunlight, the solar panel performance can be lower than in cooler, sunny seasons.

Key Factors for Heat Resilience

You can mitigate these effects by focusing on product choice and installation.

• Choose a Low Temperature Coefficient: When selecting panels, compare product datasheets. A coefficient of -0.3%/°C will perform better in heat than one rated at -0.4%/°C.
• Ensure Proper Ventilation: Professional installation is critical. Panels should be mounted with a gap between the module and roof to allow airflow, which passively cools the system. This is a core part of a quality solar system installation.
• Prioritize Quality & Maintenance: High-quality components from reliable providers are engineered for better long-term reliability. Regular checks to ensure the panels are clean and unshaded also help maintain optimal operation and prevent localized “hot spots.”