What this changes for your decision
The solar potential of Swiss roofs is revised from 50 GW to 65 GW thanks to the increased efficiency of the modules. This guide shows the elements to check in the quote and contract.
For your project, the item “winter production” should be explained in terms of the building, consumption, grid connection and contract. Ask for the source, date and, for calculated values, the method used.
For your project: Compare façade and roof using monthly results. Account for sun position, shading, snow, reflections and winter electricity needs.
Three checks before signing
1. Feasibility
Check structure, roof condition, fire, access, connection and authorizations before ordering.
2. Perimeter
Distinguish between house, facade, large installation and special surface, because the procedures differ.
3. Decision date
Have rules, aids and technical proofs confirmed just before signing.
References for “Winter” for your project
- BFH, Photovoltaic Barometer 2025: The solar potential of Swiss roofs is revised from 50 GW to 65 GW thanks to the increased efficiency of the modules.
- Swissolar, fire protection of PV facades: Swissolar announces a transition to a state-of-the-art paper which will replace the VKF/AEAI note in 2027.
Note the date of consultation and the scope of each source. National information does not replace or local rate or technical validation of your project.
Compare quotes on a solid basis
Ask for a reference variant and a conservative variant. Each must separate investment, self-consumption, injection, aid, schedule and responsibilities. You will see if the result holds with a less favorable hypothesis.
For the item “winter production”, the quote should state the data to confirm before work starts, who will check it and how changes will be handled.
Your next step
Prepare utility bill, roof information, existing contracts and comparable quotes. Answer in writing to open questions, then compare net price, annual profit and contractual consequences.