It’s a beautiful, sunny day on the Sunshine Coast. You open your solar monitoring app, expecting to see record-breaking generation, but the numbers are underwhelming. You’ve invested thousands in a solar system to save money and reduce your carbon footprint, so it’s incredibly frustrating when it doesn’t seem to be working as promised.
“Why is my solar system not producing enough power?” is one of the most common questions we get from local homeowners. The answer isn’t always simple, as several factors can influence your system’s performance.
In this guide, we’ll walk you through the seven most likely culprits for low solar output and provide practical steps to help you get your system back to peak performance.
Understanding “Normal” Production
Before we dive into the problems, it’s important to understand that your solar system’s output isn’t static. It changes based on:
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Time of Day & Year: Production peaks at midday and in summer. A 6.6kW system won’t produce 6.6kW at 8 AM in winter.
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Weather: Clouds, rain, and even extreme heat can reduce efficiency.
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System Orientation: North-facing panels produce the most energy overall, while East/West panels have different peak times.
If your production is consistently low compared to previous years or similar days, then it’s time to investigate.
The 7 Common Causes of Low Solar Production
1. Shading: The Silent Performance Killer
This is the number one reason for poor performance. Trees grow, new buildings go up, and even a small amount of shade on a single panel can have a disproportionate impact on the entire string of panels.
2. Dirty Panels: Dust, Pollen, and Salt
On the Sunshine Coast, salt spray from the ocean, along with dust, pollen, and bird droppings, can create a grime layer that blocks sunlight. A dirty system can lose 5–15% of its efficiency.
3. Inverter Issues: The “Brain” is Offline
Your inverter converts the DC power from the panels into usable AC power for your home. If it’s displaying a red light, an error code, or a blank screen, your entire system is likely offline or severely limited.
4. Grid Voltage Issues (Curtailment)
On very sunny days when many homes are feeding solar power into the grid, the grid’s voltage can rise. To protect itself, your inverter may automatically reduce its output or shut down completely. This is known as “curtailment.”
5. System Age & Degradation
Like all technology, solar panels degrade over time. Most reputable brands lose about 0.5% of their efficiency each year. A 10-year-old system will naturally produce less than a brand-new one.
6. Wiring or Connection Problems
Loose connections, corrosion from salt air, or even rodent damage to cables can interrupt the flow of electricity, leading to intermittent drops in power or complete string failure.
7. Unrealistic Expectations
Sometimes, the problem isn’t the supply; it’s the demand. If you’ve added a pool, an electric vehicle, or new air conditioning since installing solar, your system might be working perfectly but simply can’t keep up with your new energy needs.
Troubleshooting Steps for Homeowners
Before calling a professional, there are a few safe and simple checks you can do:
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Visual Inspection: From the ground, look for any obvious shading from trees or debris on the panels.
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Check the Inverter Screen: Is there an error code or a red light? Note down any codes.
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Compare Data: Look at your monitoring app. Is the drop in production sudden or gradual? Compare a sunny day now to a sunny day from a previous year.
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Check Your Breakers: Ensure the “Solar Supply Main Switch” in your switchboard hasn’t tripped.
When to Call a Professional
If you’ve done the basic checks and the problem persists, it’s time to call in an expert. You should never attempt to fix electrical issues or get on the roof yourself. A CEC-accredited solar electrician can:
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Perform a professional panel clean and inspection.
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Diagnose complex inverter error codes and manage warranty claims.
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Test the voltage and current of each panel string to identify faulty components.
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Analyze your grid voltage and liaise with Energex if curtailment is an issue.
Final Thoughts
A solar system is a fantastic investment, but like any other part of your home, it requires occasional attention to perform at its best. By understanding the common causes of low production—from shading to inverter faults—you can take the right steps to ensure you’re getting every watt of power you paid for.
