What exactly is a Suntag report?
A 16-page PDF analysis of a single location in Switzerland or Liechtenstein, ready in under ten seconds. At its core is a sun-exposure and shading study – how much sun the spot gets through the year, and how the surrounding terrain cuts into that by season. Around it sit the layers that shape everyday life there: road and rail noise, public-transport access, mobile and broadband coverage, and long-term climate averages.
What is sun exposure, and why does it matter?
Sun exposure is how much direct sunlight a location actually receives over the year – governed by the season, the sun's path, and the hills, ridges or mountains that sit on its horizon. It drives daylight, heating and cooling costs, and how much use you'll really get out of a south-facing balcony. Suntag calculates it for any Swiss address, day by day across the whole year, from the real terrain model published by swisstopo – not just the astronomical sun position simpler calculators use.
How many hours of sunshine does a house need?
For good living comfort, a location should get several hours of direct sun even in winter; pure north-facing or heavily shaded valley locations score markedly worse. The Suntag report shows the effective sun exposure of your location month by month, including the critical winter months from November to February, when surrounding mountains and hills block the sun the longest.
How is it calculated?
From a digital terrain model of Switzerland – a 25-metre elevation grid published by swisstopo – combined with the sun's exact path through the sky across the whole year. For your point, Suntag traces the horizon in every direction, works out the moment the sun clears each surrounding hill and mountain, and adds up the sunlit time that results.
What does the report not take into account?
Trees and vegetation, buildings and other structures, and any construction – existing, planned or built after the report is generated. The terrain model deliberately excludes trees and buildings, so the analysis reflects the shape of the land itself, not what's built or growing on it. Weather and air quality aren't modelled either. All figures are estimates and can differ from what you experience on site.
How accurate is it?
The terrain data and the sun-path calculation are exact. How closely the report matches what you'll actually see depends on what forms the horizon at your location: where it's hills and mountains, the report captures it well; where it's a neighbouring building or a row of trees, it can't – those aren't in the terrain model. Open, rural locations track reality more closely than dense urban ones.
Can I use it to decide whether to buy, rent or build somewhere?
It's a useful input, not a verdict. The report is general information – not a survey, an expert opinion, or architectural, legal or financial advice – and shouldn't be the sole basis for a decision. Use it to compare locations side by side, catch an obvious problem early, or walk into a viewing with the right questions already in hand.
Can I use it to plan solar panels?
Yes. Alongside showing how sunny a spot is, Suntag maps the exact horizon around it – precisely the shading input a solar-yield calculator needs to estimate what a panel installation at that location would actually produce.
