How to Tell If Your Solar Panels Are Working
The quickest way to know if your solar panels are working is to look at your inverter. A steady green light on a sunny day means the system is generating. From there you can confirm it with your generation meter, your monitoring app and your electricity bills. If the inverter shows a red or amber light, or your readings have flatlined, the system may have a fault worth checking.
Quick Answer
To tell if your solar panels are working, check the inverter: a steady green light during daylight means it is generating. Confirm it by watching your generation meter climb during the day, checking your monitoring app for live output, and looking for lower electricity bills. A red or amber inverter light, a meter that is not moving, or bills that have crept back up are the main signs something has stopped.
Fact-checked by John Rooney, Solar Energy Editor. Editorial policy
5 ways to check your solar panels are working
You do not need any tools or an electrician for the first checks. Run through these in order on a bright day for the clearest picture.
1. Check the inverter light
The inverter is the box, usually in a loft, garage or utility area, that turns the panels' DC power into AC for your home. On a sunny day a steady green light means it is generating normally. A red or amber light, a flashing light, or a fault code on the screen means it has detected a problem. Note any code shown, as it points to the cause.
2. Read the generation meter
Most systems have a generation meter that counts total kWh produced. Note the number, wait a few hours of daylight, and check it again. If it has climbed, the panels are working. If it has not moved at all during good sunlight, something is wrong.
3. Open your monitoring app
If your system has online monitoring (SolarEdge, GivEnergy, Enphase, Tesla and others), the app shows live and historical output. A normal day shows a smooth curve that rises through the morning, peaks around midday and falls in the afternoon. A flat line during daylight, or one string of panels producing far less than the rest, signals a fault.
4. Compare your electricity bills
A working system lowers your daytime grid import. If your bills have crept back up to where they were before the panels went in, with no change in how you use power, the system may not be generating as it should. Your Smart Export Guarantee payments are another clue: if export payments have dropped, so has generation.
5. Sense-check the output against the weather
Output naturally rises and falls with sunshine, season and the time of day, so lower numbers in winter or under cloud are normal, not a fault. Compare a bright day now with a similar bright day a few months ago. See expected solar output and how panels behave on cloudy days before assuming the worst.
Signs your solar panels have stopped working
| Sign | What it usually means |
|---|---|
| Red or amber inverter light | The inverter has faulted or shut down. Note the code. |
| No light on the inverter at all | No power to the inverter, a tripped isolator switch, or a failed unit. |
| Generation meter not moving in daylight | The system is not generating. |
| Flat line in the monitoring app | A fault, a lost connection, or the system offline. |
| Bills rising with no change in usage | Reduced or zero generation feeding the home. |
| One area of the array under-producing | Shading, dirt, or a faulty panel, string or optimiser. |
Not every dip is a fault. Dirty panels, new shading from a grown tree, or a simple tripped switch are common and easy to fix. Try resetting the system at the isolator switch (off, wait a minute, back on) before assuming a serious fault.
What to do if your panels are not working
- Note the inverter fault code and any error in the monitoring app.
- Check the AC and DC isolator switches are on, and reset the system once.
- Rule out the easy causes: dirty panels, new shading, a tripped breaker.
- Check whether your panels simply need a clean.
- If it still will not generate, book an MCS-certified installer for a repair or inspection.
Inverters are the most common failure point and typically last 10 to 15 years, less than the panels themselves, so an ageing system that stops often needs a new inverter rather than new panels. Regular maintenance catches most issues early.
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Solar Panels Working FAQ
How do I know if my solar panels are working?
Check the inverter first: a steady green light during daylight means it is generating. Confirm it by watching your generation meter climb through the day, checking your monitoring app for a normal output curve, and looking for lower electricity bills. A red or amber inverter light, a meter that is not moving, or rising bills are the main signs something has stopped.
How can I tell if my solar panels are generating electricity?
Your generation meter is the clearest proof. Note the kWh total, wait a few hours of daylight, then check again. If the number has gone up, the panels are generating. A live monitoring app showing output rising through the day confirms the same thing.
What does a red light on my solar inverter mean?
A red or amber light means the inverter has detected a fault and may have stopped generating. Note any error code on the display, as it points to the cause. Try switching the system off and on at the isolator. If the red light stays, book an MCS-certified installer to inspect it.
Why are my solar panels producing less than usual?
Lower output is often normal: winter, cloud, shorter days and a lower sun all reduce generation. Faults that cut output include dirty panels, new shading from a grown tree, a tripped switch, or a failing inverter, panel or optimiser. Compare a bright day now with a similar bright day months ago before assuming a fault.
Do solar panels stop working completely if one fails?
Usually not. Most systems keep generating even if one panel or optimiser fails, you just lose that panel's share of the output. A string inverter system may show a bigger drop if a whole string is affected. Monitoring at panel or string level helps pinpoint which part has failed.
How often do solar panels need checking?
Panels themselves are low maintenance and often need only an occasional clean and a glance at the monitoring app. A professional inspection every few years, and replacing the inverter at around 10 to 15 years, keeps a system generating at its best.
For more, see how to set up solar monitoring, what output to expect, and keeping a system healthy.
Related Guides
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Solar Panel Repair
Common faults, repair costs, and when the warranty should pay.
Maintenance Guide
Cleaning, monitoring, warranties, and lifespan.
Solar Panel Output
How much electricity solar panels produce by system size in the UK.
Solar Panel Cleaning
DIY vs professional cleaning, costs, how often, and effect on output.
How Solar Panels Work
Plain-English guide to solar PV technology.
Sources
Last updated: July 2026
John Rooney is the founder of Solar Info and has been covering the UK solar energy market since 2023. He researches every battery and inverter brand against manufacturer datasheets, MCS and Ofgem data, and feedback from the MCS-certified installers in our directory before publishing.
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