The signs that a solar installation is underperforming

An installation’s production naturally varies with the weather and the season. The difficulty is telling a gray week, which is normal, from a real loss of production. Here are the most frequent causes, and the sign that gives each one away.

The inverter that drops out

It is the most clear-cut failure: the inverter stops or restarts in a loop, and production falls to zero or comes in fits and starts. The sign: entire days at zero production while the sky was clear. It is also the simplest failure to spot with monitoring, and the most expensive one to ignore.

The shading that was not there at installation

A tree that has grown, a neighboring construction, a new chimney: shading evolves over the years. The sign: a dip that comes back at the same time every day, more pronounced in certain seasons when the sun is low.

Soiling and deposits

Dust, pollen, bird droppings, leaves in the corners: soiling brings production down progressively, in a uniform way. The sign: a gap that widens slowly over months, without jolts, and that corrects itself after a good rain or a cleaning.

The degradation of a panel or a string

A failing panel can drag its whole string down. The sign: a clean step down in production, which corrects itself neither with the weather nor with cleaning.

The common thread: without a reference, you see nothing

All these signs share the same condition: you have to compare actual production to expected production. To the naked eye, an installation losing 10% goes unnoticed. That is precisely the role of monitoring like SOLARSPLIT Monitoring, which follows your multi-brand installations in a single app: making the gap visible so you can act early.

To understand why the manufacturer’s app is not always enough, read why monitoring your production does not stop at the inverter app. And if you are still at the project stage, the warranties covering these failures are checked in the quote: how to read a solar quote.