How can I tell if my solar system is underperforming?

The safest way to check is to look at what your system already tells you. Compare your monitoring app or inverter display on similar sunny days, check for any error messages or warning lights, and look for a change in your power bills. If something looks wrong, note what you see and call a licensed installer. Do not go on the roof or open any equipment.

What is normal?

Solar output changes all the time, and most of those changes are not faults.

• Weather. Cloud and rain reduce output. Panels still work under cloud, just at a lower level.
• Season. Winter days are shorter and the sun is lower, so output is usually lower than in summer.
• Heat. Very hot panels tend to be a little less efficient.
• Shade. Trees, neighbouring buildings and structures can shade panels at certain times of day, and that changes through the year.
• Age. Panels slowly produce a little less as they age.

Our article on how a solar power system works in a Brisbane home explains how these things fit together.

What signs are worth acting on?

• An error message or warning light. See our article on solar inverter red lights and errors.
• Little or no generation in good sun. Your app or display shows low output in clear conditions.
• A sudden change in your bills. You are buying more power from the grid than usual.
• Output that stops or drops at the same time each day. This can be shade, a limit on how much you can export, or a fault. Our article on why solar export is limited explains one common cause.
• Visible damage. A cracked panel or debris you can see from the ground. Do not climb up to look closer.

What if my app shows no data?

A monitoring app can lose its connection while the system keeps working. Check the inverter’s own display or lights from where you can see them, and compare your bill. If the app stays offline, tell your installer.

Can dirty panels be the cause?

They can. Dust, leaves and bird droppings may reduce output. Cleaning is not a job to try yourself, because roofs are dangerous places and falls cause serious injuries. Arlite’s team can clean panels as part of a visit, and offers solar cleaning.

How do I compare fairly?

Compare like with like. A sunny day in summer is not comparable with a cloudy day in winter. Look at clear days at a similar time of year, and look at the pattern over several days rather than one reading. The more notes and screenshots you can give the installer, the faster they can find the cause.

What will a licensed installer do?

Arlite’s team tests the panels, inverter, wiring and connections methodically, explains the cause plainly, and repairs and retests the work. They can also diagnose and repair systems they did not install. Read more about solar fault finding on the Arlite website.

If you rent, report the problem to your landlord or property manager rather than trying to arrange anything yourself.