A photovoltaic system consists of five core components: the solar modules on the roof, the substructure, the inverter, the cabling with protection technology and the meter. Optionally, a battery storage and an energy manager are added. Each component has a clear task – together they turn sunlight into usable household electricity.
Key points in brief
- The modules generate direct current, the inverter turns it into household-compatible alternating current.
- The substructure supports the modules and is structurally the underestimated part of the system.
- The meter is switched to a measurement with feed-in as soon as the system feeds in.
- Battery and energy manager are sensible additions, but not a must.
- The quality of the system is decided less by the individual component than by the interaction.
What does a photovoltaic system actually consist of?
From the street you can only see the modules – the rest of the system remains hidden. Yet it is precisely the invisible parts that decide on yield and longevity. Here is the overview before we go into detail:
| Component | Job | Lifespan (guideline value) |
|---|---|---|
| Solar modules | Convert sunlight into direct current | 25–30+ years |
| Substructure | Carry modules and hold them securely on the roof | Lifespan of the system |
| Inverter | Convert direct current into alternating current | 10–15 years |
| Cabling & protection technology | Conduct, protect, monitor electricity | Lifespan of the system |
| Meter | Measure consumption and feed-in | provided by the utility |
| (optional) battery storage | Store excess for later | ~10–15 years |
| (optional) energy manager | Control consumers, increase self-consumption | Lifespan of the system |
Guideline values, As of: July 2026. The actual lifespan depends on the product and conditions of use.
The solar modules: the heart on the roof
The modules convert sunlight directly into electrical electricity – without moving parts, without wear and tear in the mechanical sense. A modern module in residential roof format today delivers around 430 to 500 watts peak power and consists of many individual solar cells connected in series and laminated weather-proof between glass and backsheet.
Which cell technology is in the modules and why almost everyone today decides on a specific design is explained in the article Monocrystalline vs. polycrystalline. How much power a module gets out of the available light is a question of efficiency.
Important to understand: modules deliver direct current (DC). A washing machine cannot do anything with that – for that you need the inverter.
The inverter: translator between roof and household
The inverter is the technical centre of the system. It converts the direct current of the modules into alternating current (AC), as the house grid and all devices need it. At the same time, it ensures that the modules always run at the optimal operating point, and provides the data for monitoring.
Because it is the only component that works actively all the time, its lifespan is shorter than that of the modules – a replacement over the course of the system's life is normal and planned for. Which types there are and what is important when making a choice is covered in a separate article The inverter: tasks, types, selection.
The substructure: underestimated and decisive
The substructure connects the modules and the roof. What sounds simple is structurally demanding: the construction must absorb wind and snow loads without damaging the roof covering, and over decades. Depending on the roof type – tile, sheet metal, flat roof, eternit – different systems are used.
To be honest: this is where clean work separates from sloppy work more strongly than with any other component. An incorrectly placed roof penetration only shows up years later as a leak. That is why the choice and installation of the substructure belongs in experienced hands.
Cabling, protection technology and meter
Between modules, inverter and house grid lie cables, fuses and protection devices – for example against overvoltage. This electrical installation is strictly specialist work and is tested at the end by an independent inspection.
The existing electricity meter is switched by the grid operator to a measurement that can record both the consumption from the grid and the feed-in of the excess. In older houses, an adaptation of the meter box is sometimes necessary – you only see this during the site visit.
Optional: battery and energy manager
Two additions increase the benefit, but are not a mandatory component:
A battery storage saves the surplus midday electricity for the evening and night, thus increasing self-consumption. Whether this pays off is a separate question – to be read in the battery storage guide.
An energy manager controls consumers such as the heat pump, wallbox or boiler so that they run as much as possible when the sun is shining. Even without a battery, self-consumption can be noticeably increased in this way – the levers for this are shown in optimising self-consumption.
When clients ask us where they can save on the budget, the answer is rarely "on the module". Modules are generally good across the board today. You should never save on the substructure and the electrical installation – these are the parts whose defects you do not see and which become the most expensive in the event of damage. A visible premium module on a wobbly substructure is the wrong prioritisation.
Frequently asked questions
Which is the most important component of a solar system?
There is no single most important one – modules and inverters are the active components, but the system is only as good as its weakest link. A high-quality substructure and a clean electrical installation are equally crucial for longevity.
Why does the inverter have a shorter lifespan than the modules?
Because it is the only component that continuously works electronically and generates heat in the process. 10 to 15 years is a common guideline value; a replacement during the system's lifespan is normal and not a malfunction.
Do I strictly need a battery?
No. The system works and pays for itself in many cases even without one. The battery is an addition that increases self-consumption – whether it makes sense or not depends on the consumption profile.
Can I combine components from different manufacturers?
As a rule, yes – however, modules, inverters and batteries must be technically compatible with each other. Exactly this coordination is part of good planning, so that in the end all parts work together reliably.
Free initial consultation
From the idea to the finished system – from a single source.
We plan all components coordinated with each other and install them professionally. We will advise you on your situation free of charge and without obligation.
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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, manufacturer documentation.
Last updated: 9 July 2026 · Author: ecoEn editorial team
