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solar output dropped heaps this year why

The question, put plainly: Why is my solar producing less than it used to?

The short answer

The usual causes in order are soiling, new shading, an inverter fault, and export limiting by the network. Panel degradation is real but far too slow to explain a sudden drop.

TradieAnswers editorial · written in-house and sourced to the authorities listed below

Checked against 5 published sources, listed in full at the end of this page. How we source this

Panels degrade at a fraction of a percent per year, so a noticeable drop between one year and the next is almost never the panels wearing out. Work through the possibilities in order of likelihood.

Check in this order

  1. Soiling. Dust, bird droppings, salt and pollen build up, and in areas with long dry spells the effect is significant. Rain does not clean panels as well as people assume.
  2. Shading. A tree that has grown, a new neighbouring building, a new antenna or a flue. Shading one part of a string can cut the output of the whole string on a string inverter system.
  3. Inverter faults and errors. Check the display or the app for error codes, and check whether one string reports zero.
  4. Export limiting. Some networks limit or curtail export at times of high generation, which reduces what you are paid for without reducing what you consume.
  5. Consumption changes. If self-consumption has gone up, your generation may be unchanged while your export has fallen.

What to do about cleaning

Cleaning helps, and getting onto a roof to do it is where people get hurt. Panels are slippery, roofs are unforgiving and the gain is not worth a fall. Ground-level water-fed poles work for many single-storey homes, and professional cleaning is inexpensive relative to the risk.

Who does this work

You need an accredited solar installer

Because a solar array is a live DC system wired into the switchboard, and both sides of it are licensed electrical work.

Depending on the cause it can also involve electrician.

This is licensed work in every Australian state and territory. Check a licence in your state

Before you call anyone

  1. Compare the same month year on year rather than month to month. Australian solar output halves between summer and winter and most reported faults are seasons.
  2. Check the inverter display or app for an error code and write it down.
  3. Look at the panels from the ground for shading that was not there when the system went in, which is usually a tree.
  4. Find your original installation paperwork. Inverter warranties commonly run five to ten years and panel warranties much longer.

Sources

Every source below was fetched and its response recorded on the date shown. Where a government site blocks automated clients, that is noted rather than reported as a successful check.

  1. Small-scale Renewable Energy Scheme · Clean Energy RegulatorChecked 2026-08-10 · responded 200 OK
  2. About accreditation · Solar Accreditation AustraliaChecked 2026-08-10 · responded 200 OK
  3. For consumers · Clean Energy CouncilChecked 2026-08-10 · responded 200 OK
  4. Australian Energy Regulator · Australian Energy RegulatorChecked 2026-08-10 · responded 200 OK
  5. SafeWork NSW · SafeWork NSWChecked 2026-08-10 · responded 200 OK

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