How solar panels work

How solar panels work

How do solar panels work? 


A solar installation converts the energy radiated by sunlight into usable electricity. The solar modules on the roof capture the sun’s rays with the help of solar cells and produce direct current. The direct current is then converted into alternating current, i.e. electric current, by the inverter.

Solar electricity is therefore the electricity produced by the photovoltaic effect in solar cells. No exhaust emissions are produced as the electricity is generated.

The following figure shows how a solar installation works, including the positioning of the most important elements in the house:


  1. Solar modules (on-roof)
  2. Solar modules instead of roof tiles (in-roof)
  3. Smart energy control system
  4. Inverter
  5. Fuse box/panel
  6. Boiler for hot water
  7. Battery storage device
  8. E-charging station
  9. Heat pump

Until a few years ago, a lot of grey energy was needed to manufacture solar modules. Grey energy refers to the amount of energy needed to manufacture and provide a product. From an energy perspective, this meant that solar installations would take ten years to pay for themselves.


The production processes for solar modules have since been significantly improved and, in terms of energy, solar installations now pay for themselves after 18 months. Calculated over the entire 30-year service life of a solar installation, solar panels produce 14 to 20 times more energy than is needed for their production.

How a solar module works

Solar modules can convert sunlight into electricity. This is made possible by the semiconductors (silicon) that conduct the electricity. As soon as sunlight shines on the solar panel, electrons are stimulated. The electrons then move through the layers of the solar module and on to the inverter. The electrons transport the current to where the energy is needed.


The energy goes directly to the relevant end consumer (light bulb, PC, battery, a.s.o.), where the electricity is available for later use.



Solar modules – also called solar panels – consist of many small solar cells. If many solar modules are connected to each other, this is called a solar installation. 


Construction of a photovoltaic system

Solar modules

Solar module – also called solar panels – convert solar energy into electricity. They consist of several layers and are usually mounted on the roof.


The task of the inverter is to convert the direct current into the grid-standard alternating current. At the same time, it controls the entire system.

Electricity meter

A meter measures the electricity fed into the grid and the electricity drawn from the grid.

Energy storage system (optional)

The energy storage system stores the surplus solar power. This increases the share of self-consumption, which in turn reduces electricity costs.

Smart energy control system (optional)

Our smart energy control system switches on the energy-intensive consumers when solar power is available. This increases self-consumption, so that less external coal-fired and nuclear power is needed.

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Which solar installation is right for me?

When choosing the right solar installation, you should not only consider the required consumption, but also the size and current characteristics of your roof. You can also choose between an on-roof or roof-integrated system, and from a range of different solar module colours.


  • Household consumption


The first thing to do is to determine your household’s annual electricity consumption. The solar installation should cover this as a minimum.



  • Roof surface area


The surface area of the roof determines how many solar modules can be installed and thus what maximum power can be achieved. It is important to arrange the modules in such a way that your household’s electricity consumption is covered.

Required power of the photovoltaic system according to household size

The electrical power of a photovoltaic system is expressed in kWp (“kilowatts peak”). Depending on location and efficiency, each kWp can generate an average of 800 to 1,300 kilowatt hours (kWh) per year in Switzerland. The following table shows the average power required based on size of household and the resulting size of the solar installation.

Person household Performance in kWp Size of the solar system
3 kWp ca. 19 m²
3 kWp ca. 19 m²
4 kWp ca. 25 m²
7 kWp ca. 40 m²
10 kWp ca. 60 m²
More information about costs

Further selection criteria


«As a general rule, we recommend aligning the size of the PV system with your consumption or choosing a larger system.»


Condition of the roof


A solar installation has a lifespan of 30 years, which means that the roof should be designed to last at least that long. If the roof is already porous or older than 40 years, an in-roof system is the best option.


On-roof or in-roof


In Switzerland, on-roof installations are the most popular choice. The solar modules are mounted on a substructure, while the original roof remains intact. On-roof systems are inexpensive and can be installed very quickly.


With an in-roof system, the photovoltaic system replaces the roof covering. This option can therefore be considered for new buildings or if you have an old roof that needs to be renovated. The solar modules are available in a range of different colours. By matching the colour to your existing infrastructure, you can achieve a particularly elegant look. An in-roof system is about 20 % more expensive than an on-roof system. To make up for this, a separate roof covering is not required with an in-roof system.




Desired look


At Helion, solar panels are available in classic silver-grey, anthracite and other colour shades on request.


Solar panel installation

The installation costs are fully included in the price of the solar panels.

We install the system with our team of experienced professionals: electricians, roofers, carpenters, plumbers, sheet metal workers.

Installation takes between two days and one week, depending on the size of the solar panel system.

Solar panel maintenance

We ensure the highest quality when selecting components and installing your system. Our photovoltaic systems have an average service life of 30 years and are extremely low maintenance. You will receive a guarantee of 20 to 25 years from the module manufacturer. Only the inverter should be replaced every 12 years.


You also have the option of concluding a monitoring contract with Helion, so that you are covered for the full-service life of 30 years. We also guarantee the energy output for the first ten years, ensuring the long-term operation of your PV system (all details can be found in the GTCs).



More reasons to choose Helion


With Helion, you get a photovoltaic system of the highest quality at affordable prices. From as little as CHF 10,000, including subsidies and tax savings, you can become your own electricity producer and protect yourself from rising electricity costs. And last but not least: you will be making a positive contribution to the environment.