What to check if output is low
- Dirty panels: dust, bird droppings or leaves can cut output a lot. Clean them early or late in the day.
- New shade: a growing tree or a new building can shade part of the panels for hours.
- Inverter errors: look for a red or orange light, an alarm, or an error code in the inverter app.
- One string or panel not working: the app may show one string producing much less than the others.
- Loose or damaged wiring: ask a qualified installer to inspect it. Do not open electrical parts yourself.
- Season and weather: winter and cloudy months produce much less, so compare a full year when you can.
- Wrong reading: check you used the production meter or inverter figure, not grid import or export.
Common questions
How much should my solar panels produce?
A rough rule is system size in kW, times the daily sun hours at your location, times about 0.8 for normal losses. A 5 kW system with 5 sun hours should make about 20 kWh a day on average.
Why does my output change through the year?
Daylight length, sun angle, temperature and clouds all change with the season. Summer months can be far higher than winter months.
How much do panels lose with age?
Most panels lose about half a percent of output each year, so a 10 year old system makes a little less than a new one.
This is an estimate based on average sunshine for your area, not a diagnosis. For a serious drop in output, ask a qualified solar installer to inspect your system.