Data sources

Where our data comes from.

This platform uses only public federal data. All sources are documented below.

SFOE Sonnendach (ch.bfe.solarenergie-eignung-daecher)

Roof solar potential

Per roof surface: usable area, annual global irradiation, orientation, tilt and suitability class 1–5. Computed from the swisstopo LiDAR terrain model and a MeteoSwiss irradiation model.

www.bfe.admin.ch/bfe/en/home/supply/digitalization-and-geoinformation/digital-applications/solar-roof.html →

swisstopo SearchServer (api3.geo.admin.ch)

Addresses & coordinates

Over 98% of all Swiss addresses. Results are returned in LV95 (EPSG:2056) — the official Swiss coordinate system.

api3.geo.admin.ch/services/sdiservices.html#search →

swisstopo WMTS (wmts.geo.admin.ch)

Maps and aerial imagery

Pixelmap (pixelkarte-farbe) and aerial (swissimage). Federal tile servers, no authentication required.

www.geo.admin.ch →

MeteoSwiss (via Sonnendach)

Climate data

Historical global irradiation 1991–2020, indirectly through the Sonnendach model.

www.meteoswiss.admin.ch →

Methodology

Our calculations

Every assumption is disclosed. You can reproduce the result yourself.

Panel density200 W / m² (≈ 0.20 kWp/m²)

Layout factor0.85 (gaps, obstacles)

Performance Ratio0.80

Investment costCHF 2'000 – 2'500 / kWp

Electricity price (own/feed-in mix)CHF 0.15 – 0.22 / kWh

CO₂ factor (CH mix)0.128 kg CO₂ / kWh

What we do NOT use

No third-party trackers. No cadastral data. No credit checks. No advertising cookies.

Licences & attribution

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