As a guideline value, a well-orientated solar system in Switzerland delivers around 950 to 1,100 kilowatt hours per kilowatt of installed capacity and year. The exact value depends on orientation, pitch, shading and location – in the Alpine region it is higher, in the foggy Swiss Plateau winter lower. For rough planning, the value of around 1,000 kWh per kWp is a usable rule of thumb. (As of: July 2026)
Key points in brief
- Guideline value for the region: around 950 to 1,100 kWh per kWp and year with good orientation.
- 'Per kWp' makes systems comparable – regardless of their size.
- Moving the value up: good south orientation, optimal pitch, no shading, sunny location.
- Downwards: shading, unfavourable orientation, a lot of fog – every factor costs a part.
- The value is a guideline value, not a guarantee: The weather fluctuates noticeably from year to year.
What does 'yield per kWp' mean?
The key figure sounds technical, but is the most honest benchmark of all. The kWp – kilowatt-peak – describes the standardised power of a system; it says how big it is. The yield per kWp says how much electricity each of these kilowatts actually delivers over the year. Only this figure makes systems comparable: A large system produces absolutely more than a small one – but whether it produces well only becomes apparent when the yield is related to the power.
An example makes it tangible: A 10 kWp system with a yield of 1,000 kWh per kWp delivers around 10,000 kWh a year. The same system in a worse location or with shading might only reach 8,500 kWh – the same power, a fifth less harvest. The yield per kWp is the yardstick by which this can be read.
What yield can I expect in Switzerland?
The reliable guideline value for a well-orientated system in the region is around 950 to 1,100 kWh per kWp and year. For rough planning, the round rule of thumb of around 1,000 kWh per kWp is sufficient – easy to remember and close enough to reality to estimate orders of magnitude.
This rule of thumb is also the reason why system size and annual consumption can be brought together so easily: Roughly, 1 kWp of installed capacity corresponds to around 1,000 kWh annual yield – how to calculate the appropriate system size from this is shown in its own article. For the exact figure at your location, however, it always applies: The guideline value classifies, the binding prognosis is provided by the planning on the concrete roof.
Guideline values, as of: July 2026 – the actual yield depends on location, orientation and shading and fluctuates from year to year due to the weather.
Which factors move the yield up or down?
The guideline value is an average – your roof is above or below it, depending on four factors:
| Factor | Impact on the yield |
|---|---|
| Orientation | South highest; East/West slightly less; North significantly less |
| Pitch | a medium angle is ideal; very flat or very steep costs a little |
| Shading | the largest single reduction factor – even a little shadow has an effect |
| Location/Position | sunny and higher-lying locations deliver more than the foggy valley floor |
Simplified overview, as of: July 2026. The factors work together; the exact prognosis is provided by the site analysis.
Two of these factors deserve a second look. Shading is the factor that many underestimate: A chimney, a tree, the neighbouring building – even a shadow that wanders over part of the system daily costs more yield than its area suggests, why this is so is explained in the guide to shading. Orientation and pitch, on the other hand, are less critical than often assumed: A roof that deviates slightly from the south or a not quite optimal angle costs only a few percent – good is usually enough here, it does not have to be perfect.
Why does the Alpine location deliver more – and the winter less?
Two geographical effects characterise the Swiss yield in particular. The first is the altitude: Above the fog line, the sun shines in winter, while the Swiss Plateau lies under the high fog cover. Alpine and higher-lying locations therefore deliver more over the year – and above all in the winter half-year, when electricity is most valuable. This is the reason why alpine solar systems are discussed as a supplement to valley production.
The second effect is the season. The yield is distributed very unevenly in Switzerland: The larger part falls into the summer half-year, the winter contributes significantly less – shorter days, low sun, fog in the Swiss Plateau. This is not a defect of the system, but physics, and is priced into every serious yield calculation. Those who want to classify winter production realistically will find the details in the guide Photovoltaics in winter. For the annual figure: The guideline value of around 1,000 kWh per kWp is already the average over the whole year, summer and winter added together.
'How much does the system yield?' is one of the first questions in almost every conversation – and we deliberately answer with a range, not with a point score. Around 950 to 1,100 kilowatt hours per kilowatt, we say, and then look at the concrete roof: How does it face the sun, does anything cast a shadow, how steep is it? What we avoid is the temptingly exact number – 'Your roof makes 10,437 kWh a year'. Such pseudo-accuracy withstands no weather reality: Two consecutive years can differ noticeably simply because of the weather, and a single cloudy summer says nothing about the system. We therefore calculate with honest guideline values and add that the value fluctuates. Those who know their real figure after the first year of operation have a better yardstick than any prognosis anyway.
Frequently asked questions
How many kWh does a 10 kWp system deliver a year?
As a guideline value, around 9,500 to 11,000 kWh – calculated with 950 to 1,100 kWh per kWp with good orientation. The exact value depends on location, orientation and shading and fluctuates from year to year due to the weather. For the order of magnitude, the rule of thumb of 1,000 kWh per kWp is usable.
Why does the yield fluctuate from year to year?
Because the weather fluctuates. A sunny year delivers noticeably more than a cloudy one, without anything having changed in the system. That is why one never assesses the yield on a single year, but on average over several – and it is best to compare the same months over the years.
Does a south-facing roof really bring much more than east-west?
Less than many think. South delivers the highest yield per module, but the deviation for east or west orientation is often only a few percent – and on a flat roof this is partly compensated for by the larger number of modules. Shading costs more yield than a slight deviation from the south.
How do I find out the yield specifically for my roof?
An initial assessment is provided by the official portal sonnendach.ch with exact address. The binding prognosis is made by a specialist company with a site analysis that takes orientation, pitch and shading into account. Both together give a realistic picture – the rule of thumb alone is only the starting point.
Is the yield in the Alpine region really higher?
Yes, especially in winter: Above the fog line, the sun shines, while the Swiss Plateau lies under high fog. Higher-lying locations therefore deliver more over the year and especially in the winter half-year, when electricity is particularly valuable. For the typical single-family home in the Swiss Plateau, however, the guideline value of around 1,000 kWh per kWp remains the appropriate size.
How much photovoltaics do I need to generate 5,000 kWh?
With the rule of thumb of around 1,000 kWh per kWp and year, about 5 kWp are needed for 5,000 kWh – with today's modules with 420 to 450 watts, that is 11 to 12 modules and around 25 to 30 square metres of roof area. On a foggy Swiss Plateau roof with east-west orientation rather 5.5 kWp, in a sunny location slightly less. That is the annual yield; in winter the system only delivers a fraction of it, in summer significantly more than the daily requirement.
Free initial consultation
What your roof actually delivers.
We calculate the yield for your location – with orientation, pitch and shading – instead of handling rules of thumb. Free of charge and without obligation.
Prefer to talk? +41 78 830 83 35
Photovoltaic installer for your region →
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: SFOE, EnergieSchweiz; sonnendach.ch (SFOE/swisstopo); empirical values from the planning practice of ecoEn GmbH, Region of Zurich.
Last updated: 9 July 2026 · Author: ecoEn editorial team
