How to Tell If Production Is Low
Before assuming your system is underperforming, you need a baseline. Solar production varies significantly by season. A 6.6kW system in Brisbane typically produces:
- Summer (Dec-Feb): 30-40 kWh/day
- Autumn/Spring: 22-30 kWh/day
- Winter (Jun-Aug): 18-25 kWh/day
Check your monitoring app for daily production. If you're consistently seeing numbers well below these ranges on clear sunny days, your system may need attention.
Compare Like for Like
Compare your current production to the same month last year, not last week. Seasonal changes account for the biggest swings in output.
Common Causes of Low Production
Shading
New construction, tree growth, or antenna installations can introduce shading that wasn't present when your system was installed. Even partial shading on a single panel can significantly reduce output for an entire string of panels.
Dirty Panels
Dust, bird droppings, pollen, and leaf litter accumulate on panels over time. In most cases, Brisbane's rainfall keeps panels reasonably clean, but panels at low tilt angles or near trees may need occasional cleaning.
Cleaning Your Panels
If your panels need cleaning, use a garden hose with plain water from the ground. Never use a pressure washer, abrasive cleaners, or walk on your roof without proper safety equipment. For stubborn grime, a professional panel clean costs $100-$200.
Weather and Season
Overcast days, rain, smoke haze, and shorter winter days all reduce production. This is normal and expected. If production drops correlate with weather patterns, there's nothing wrong with your system.
Inverter Issues
If your inverter is showing error codes, entering standby during daylight hours, or frequently restarting, it may be limiting your system's output. Check our inverter troubleshooting guide for more information.
Panel Degradation
Solar panels degrade slowly over time, typically less than 0.5% per year. After 10 years, you might notice a small reduction compared to the first year, but this is gradual and shouldn't cause a sudden drop.
What to Check
Check Your Monitoring App
Look at daily production graphs. A sudden drop suggests an event (shading, fault). A gradual decline might indicate soiling or degradation.
Visually Inspect Your Panels
From the ground, look for visible debris, bird nests, heavy soiling, or physical damage. Use binoculars if your roof is high.
Check Inverter for Errors
Look at the inverter display for any error codes or warnings. Note them down to share with your installer.
Compare with Neighbours
If you know anyone nearby with a similar system, compare production. If theirs is also low, the cause is likely weather-related.
When to Get a Solar Health Check
If you've ruled out weather, shading, and soiling, and your production is still noticeably below expected levels, it's time for a professional solar health check. UV Power offers comprehensive system inspections that include panel testing, inverter diagnostics, wiring checks, and performance benchmarking.
Book a solar health check by calling 1300 887 140 or visiting our services page.
