As a rough guideline, a turnkey solar system costs around CHF 300 to 550 per square metre of roof area used (as of August 2026, before incentives). However, this figure only arises through conversion: on a pitched roof, 1 kilowatt of capacity needs around 5 to 7 m² of area, and in Switzerland, quotes are given per kilowatt peak, not per square metre. For an initial estimate, the m² figure is still good enough.
Key points in brief
- Rule of thumb for pitched roofs: 5 to 7 m² of roof area per kWp. On a flat roof with elevated rows, because of the row spacing, it's more like 8 to 12 m².
- This gives a guideline figure of around CHF 300–550 per m² – the wide range comes from system size, not module quality.
- The larger the area, the lower the price per m²: scaffolding, travel and electrical work are incurred almost independently of system size.
- The roof area from the land register or the map is never the usable area – chimneys, roof windows and edge clearances eat up a noticeable share.
- What differs regionally isn't the prices, but the incentives and the feed-in tariffs.
Why the industry doesn't quote per square metre
Anyone looking at their roof thinks in square metres. Anyone building solar systems calculates in kilowatt peak. Both are right – the two measures just measure different things.
The square metre describes the space. The kilowatt peak describes the capacity installed in that space. And because two modules of the same size can deliver different amounts of output, the m² price is a comparison figure with a built-in flaw: a cheaper module with lower efficiency lowers the price per square metre but still delivers less electricity. That's why the price per kWp is the more honest comparison figure once it comes to comparing quotes.
For an initial estimate – «does this even fit my budget?» – the m² figure works well, though. You just need to know how to convert it.
How many square metres does a kilowatt need?
A modern module measures just under two square metres and delivers around 400 to 450 watts. Purely by calculation, that would come to a good four square metres per kilowatt. In practice, you reckon with more, because space is lost between module rows, at the edges and around roof structures.
| Roof type | Area needed per kWp | Reason |
|---|---|---|
| Pitched roof, mounted parallel to the roof | around 5–7 m² | edge clearances, chimneys, roof windows |
| Flat roof, elevated south-facing | around 10–12 m² | row spacing against shading |
| Flat roof, east-west layout | around 8–10 m² | flatter mounting angle, tighter rows |
| Facade, vertical | around 6–8 m² | no shading clearances, but a mounting grid |
Guideline figures, as of August 2026. The planning for your specific roof is decisive.
The flat-roof rows surprise many people. There, the area is indeed freely available, but elevated rows cast shade on the next row – the spacing costs more area than the free orientation gains. Which layout gets more out of which flat roof is clarified in the article Flat roof: orientation and layout.
Guideline prices: what 30 to 200 m² of roof area costs
The following table combines the rule of thumb for pitched roofs (5–7 m² per kWp) with the guideline prices per kWp. It's derived, not measured – but it shows the order of magnitude involved.
| Roof area used | gives around | Guideline price, turnkey |
|---|---|---|
| 30 m² | 4–6 kWp | CHF 11,000–17,000 |
| 50 m² | 7–10 kWp | CHF 15,000–26,000 |
| 80 m² | 11–16 kWp | CHF 22,000–37,000 |
| 100 m² | 14–20 kWp | CHF 27,000–46,000 |
| 150 m² | 21–30 kWp | CHF 38,000–68,000 |
| 200 m² | 28–40 kWp | CHF 48,000–85,000 |
Guideline figures, as of August 2026, turnkey incl. installation and VAT, before incentives. The individual quote is binding.
Two things stand out. First, the width of the ranges: between CHF 27,000 and 46,000 for the same 100 m² roof lies a world of difference, explained by roof shape, tile type, accessibility, the electrical installation in the basement, and whether a storage is added. Second, the price per square metre falls noticeably with area – at 30 m² it's in the range of 400 to 550 francs, at 200 m² more like 250 to 350. The reason is fixed costs: scaffolding, travel, registrations and electrical work are incurred at almost the same level for the small system as for the large one.
From this follows a recommendation we regularly give in consultations: if the roof can take more, a generous layout is almost always worth it rather than a tightly sized system. The reasoning is in the article How many solar modules does my house need?.
Caution: roof area isn't the same as usable area
The most common miscalculation doesn't happen with the price, but with the area. On a map or in a building plan, a roof looks generous; after deducting chimneys, roof windows, dormers, antennas and the necessary edge clearances, a quarter to a third less regularly remains.
Then there's shading. A neighbour's tree that moves across the bottom row of modules at four in the afternoon doesn't make that area worthless – but it does shift the economics. How much, only a yield simulation can show; the fundamentals are in the article Shading on solar systems.
A useful first indication is provided by sonnendach.ch: there, the federal government shows area, orientation and suitability class for practically every Swiss roof. Our solar calculator uses the same official data: you enter your address there and get your roof's areas along with a guideline price range, without having to do the conversion yourself.
Does the same system cost more in Zurich than in Luzern?
No, not noticeably. Price differences within German-speaking Switzerland arise hardly at all from location, but from the roof, the access, and the complexity of the electrical installation. A complex roof in the city with narrow access and a road closure for the scaffolding costs more than a detached house in the commuter belt – but that's a question of the building site, not the canton.
What genuinely does differ regionally are two other items: the incentives, which vary considerably by canton and municipality alongside the federal one-off incentive, and your utility's feed-in tariff. Both change the economics far more than any regional price premium. For our core regions, the figures are compiled on the pages Solar systems Zurich, Winterthur, Aargau and Zug.
The question «what does the square metre cost?» comes up with us almost always on the phone, in the first conversation, before anyone has climbed onto the roof – and it's entirely fair: people want to know if they're thinking in the right order of magnitude. What we then do is always the same: we state the range honestly, and in the next sentence, we put the area into perspective. Because the figure owners give us is almost never the usable area, but the footprint of the house or the area of a whole roof slope. After the site visit, the usable figure regularly comes in a good deal lower – and the system is nonetheless often larger than expected, because the second roof surface also comes into play, which nobody had factored in beforehand.
Frequently asked questions
How many kWp fit on 120 m² of roof area?
On a pitched roof with an area requirement of 5 to 7 m² per kWp, 120 m² of usable area gives around 17 to 24 kWp. The key word is «usable»: chimneys, roof windows and edge clearances should already be thought of as deducted. On an elevated flat roof, the same area would give more like 10 to 15 kWp.
How many kWp fit on 150 or 200 m²?
As a guideline for pitched roofs: 150 m² gives around 21 to 30 kWp, 200 m² around 28 to 40 kWp. At this scale, you leave the classic single-family home range – notification, grid connection and, depending on capacity, the incentive model also change. The details are in the article Calculating system size.
What does a 30 m² solar system cost?
Around CHF 11,000 to 17,000 turnkey, before incentives (as of August 2026). That corresponds to about 4 to 6 kWp. Small systems are the most expensive per square metre, because scaffolding, travel and electrical work are spread over little capacity.
Is the price per m² a good comparison figure for quotes?
No. It rewards modules with lower efficiency, because they deliver less output for the same area and thus look cheaper on paper. Compare quotes using the price per kWp and the items included – how to do that is shown in the article Comparing solar quotes.
For a solar obligation, does the roof area or the capacity count?
That depends on the regulation. Federal requirements are linked to the building's floor area, while cantonal regulations are sometimes linked to a minimum capacity per square metre. The overview is in the article Solar obligation Switzerland.
How do I find out my usable roof area without sending someone onto the roof?
Via sonnendach.ch or our solar calculator: both access the same official federal roof data and show area, orientation and suitability per section. For the quote, a site visit is still needed afterwards – mainly because of the substructure and the electrical installation.
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Sources: Sonnendach/Sonnenfassade data from the Swiss Federal Office of Energy (SFOE), module data sheets from standard-market manufacturers 2026, ecoEn's own project calculations (Zurich region).
Last updated: 9 July 2026 · Author: ecoEn editorial team
