How Much Power Output Should I Expect from My Solar Panels in Real-World Conditions?

When you purchase a solar panel, the wattage listed on the product (for example, 200W, 300W, or 400W) reflects the panel’s performance under Standard Test Conditions (STC). These are controlled laboratory conditions that use perfect sunlight intensity, optimal temperature, and ideal panel positioning. In reality, your solar panels will rarely operate under those exact conditions.

This guide explains what you can realistically expect from your solar panels in everyday use and what factors affect their performance.

Why Real-World Output Differs from Rated Output

Several factors influence how much power your solar panels will produce in practical conditions:

1. Sunlight Intensity & Angle
   Solar panels perform best under direct, strong sunlight. The angle of the sun changes throughout the day and across the seasons. Panels tilted towards the sun capture more energy compared to flat or shaded positioning.

2. Temperature
   High heat can reduce panel efficiency. Although solar panels need sunlight, very hot conditions can actually cause a small drop in output compared to cooler, sunny weather.

3. Shading
   Even partial shading from trees, antennas, or nearby objects can significantly reduce output. For example, a shadow across just part of one panel in a series connection can affect the performance of the entire string.

4. Cleanliness
   Dirt, dust, salt, or bird droppings can block sunlight from reaching the solar cells. Keeping your panels clean is essential for maintaining performance.

5. Weather Conditions
   Cloudy or rainy days reduce the amount of sunlight available. On heavily overcast days, panels may generate only 10–30% of their rated output.

Typical Real-World Output

• Under good sunlight with minimal shading and moderate temperatures, solar panels generally produce 70–90% of their rated capacity.

• For example, a 200W panel may produce around 140–180W during peak sunlight hours.

• In less-than-ideal conditions (overcast skies, high heat, partial shading), the output can drop to 30–70% of rated capacity.

How to Maximise Solar Panel Performance

To get the most from your solar panels:

• Position correctly – Angle panels towards the sun where possible.

• Avoid shading – Set up away from trees, poles, or obstructions.

• Keep panels clean – Wipe down with a soft cloth and fresh water every few months.

• Allow airflow – Panels work more efficiently when they can stay cooler.

• Check wiring & connections – Ensure cables are secure and in good condition.

Key Takeaway

While the wattage rating on your solar panel shows its maximum potential under ideal conditions, real-world performance will vary. Expect around 70–90% of the rated output in sunny conditions, with lower production during cloudy, shaded, or very hot weather. With proper setup and maintenance, you can ensure your panels deliver reliable energy for your needs.

Need more help?
Visit our Help Centre or contact our support team if you have questions about solar panel performance or troubleshooting.