A solar system needs little care, but not none. What is needed fits into half an hour per year: comparing yield with previous years, checking fault messages, a visual inspection from the ground and a look at the utility statement. You do not have to climb onto the roof for this – and you should not either. (As of: July 2026)
Key points in brief
- The annual check takes around 30 minutes and requires no tools – only the monitoring app, electricity bill and your own eyes.
- Most important point: the yield comparison with previous years. It discovers problems that you cannot see from the outside.
- Work on the roof belongs without exception in professional hands – the risk of falling and warranty issues speak a clear language.
- A fixed date helps: many use the turn of the year or the spring, when the annual figures are available.
Why an annual check at all?
Solar systems have no moving parts and run inconspicuously for years – exactly that is their strength and their weakness at the same time. A system that does not draw attention to itself can be silently producing or silently failed; from the street, both look the same. The cases that reach us afterwards almost always follow the same pattern: the failure would have been visible in the monitoring app for months, only nobody had looked into it.
The annual check does not replace professional maintenance, but it ensures that problems are weeks instead of years old when they are noticed.
The checklist: what belongs in the 30 minutes?
| Step | What you do | What you pay attention to |
|---|---|---|
| 1. Read annual yield | Open monitoring app or inverter portal | Note production of the past year |
| 2. Compare with previous years | Keep your own list of annual values | Deviations of over around 10% without weather explanation |
| 3. Check fault messages | Message history in the app | recurring errors, acknowledged warnings |
| 4. Visual inspection from the ground | once around the house, with binoculars if necessary | slipped modules, hanging cables, heavy dirt edge, vegetation |
| 5. Reconcile statement | Compare feed-in on the utility statement with app values | rough plausibility, not rappen accuracy |
| 6. Check surroundings | trees and new builds to the south | growing shading from year to year |
As of: July 2026. The list applies to typical single-family home systems; for self-consumption community (ZEV) and business systems, accounting and contractual points are added.
There are deeper insights into the individual points: the yield comparison and the question of which deviation is normal are related to the degradation of the modules; the reconciliation of app and statement is explained in detail in Measurement and meter; and how to read the electricity bill item by item is detailed in its own article.
What to do if the yield is noticeably lower?
First: stay calm and rule out the weather. A gloomy year can noticeably depress the yield without anything being wrong with the system – comparing with neighbours or regional values helps with the classification. If the deviation remains unexplained, go through the causes from simple to complex:
1. Fault messages and inverter status – the most common finding, often solved by a restart or firmware update by the installer. 2. Compare individual strings, if the app provides this: if only one string drops, this severely narrows down the search. 3. Soiling or shading – the dirt edge on the lower edge of the module or the tree that has grown larger. When cleaning really brings something: Cleaning the solar system. 4. Call in a specialist company, if none of this works – with your noted annual values, troubleshooting is significantly faster and cheaper than with «something is wrong».
What does NOT belong in your own hands?
Clearly stated: everything that requires setting foot on the roof. Cleaning modules, straightening cables, clearing snow, «briefly tightening» fastenings – the combination of the risk of falling, sensitive modules and warranty conditions makes DIY work on the roof a bad deal. Even with snow, leaving it alone is almost always the right answer. The same applies to everything in the inverter and meter area beyond reading: work on electrical installations belongs to the specialist.
Exception in observation, not in action: if you notice marten traces around the house or under the roof, this is a reason to have the cables specifically checked.
When is a professional inspection worthwhile?
Besides your own annual check, there are occasions for the professional: after severe storms or hail, in case of an unexplained lower yield, before the expiry of warranty periods – and routinely as part of the periodic electrical inspection of your property, to which the system belongs. A well-documented system with complete annual values makes every one of these inspections shorter and cheaper.
We give customers two things at handover: activated fault messages and the recommendation to keep the annual values in a simple table – paper is sufficient. The systems where discussions about warranty or lower yield were later solved cleanly and quickly were practically always those with this table. Five figures per year, noted in two minutes, are in doubt worth more than any gut feeling.
Frequently asked questions
How often does a solar system need professional maintenance?
There is no rigid mandatory cycle for a single-family home; an inspection on a given occasion as well as integration into the periodic electrical inspection of the property is usual. Those who want to play it safe have the system professionally checked every few years.
Which yield deviation is normal?
From year to year, the yield fluctuates noticeably due to the weather – individual years can be significantly above or below the average. Less suspicious is a single weak year than a trend over several years or a sudden collapse without weather explanation.
Do I need a maintenance contract?
For typical single-family home systems usually not – the annual check plus inspection when required covers most things. It is different for self-consumption community (ZEV), business or difficult-to-access systems: there, a contract with defined response times can be sensible.
What is best to note for the system dossier?
Annual production, feed-in according to the utility statement, special events (faults, repairs, storms) and photos after extraordinary weather conditions. Together with the quote, acceptance protocol and warranty documents, this results in a dossier that is worth ready cash in warranty cases and when selling the house.
Does the app reliably show me every failure?
Only if the fault messages are activated – and even then not every creeping lower yield. That is why the annual comparison is part of it: it also finds what does not trigger an error message.
Free initial consultation
Prefer a proper check-up once?
We check the system, monitoring and documentation – and you know where you stand. Also for systems that were not built by us.
Prefer to talk? +41 78 830 83 35
Photovoltaics Switzerland – installation by a specialist company →
Swissolar-certified specialist company · ESTI installation authorisation (Art. 14 NIV) · in Zurich since 2017 · over 150 systems completed · a personal answer from the specialist company, no call centre
Sources: EnergieSchweiz, Swissolar (operating recommendations), ecoEn consulting practice.
Last updated: 9 July 2026 · Author: ecoEn editorial team
