In Valais, compare contractors using your roof, consumption and project scope. Check authorisations, professional status and written service terms instead of a general ranking.
Check the contractors Request the legal company name, comparable references and the division of work between the main contractor and subcontractors. Check authorisation for the electrical tasks. Swissolar membership and the Solarprofis label are different: verify status and activities in the current directory. Nearby premises guarantee neither competence nor repair response times.
Compare the same project Provide roof details, consumption and required functions. Compare models, layout, monthly generation, included work, exclusions and installed price. A generation forecast is not a contractual guarantee. Specify service costs, warranties and contacts. Request several suitable offers without treating three quotations as a legal requirement.
Define procedures and handover Identify the grid operator for the address and who handles each application. Pronovo provides project-specific procedures and permits third-party representation; check documents and timing. Specify payments, tests, handover records and service in the contract. A supplier name or “all-inclusive” claim cannot allocate every responsibility.
Valais example: compare an exposed roof site Consider a home whose roof needs careful assessment of wind, snow and access. This example assumes no uniform conditions across Valais. Request a site survey and calculation method rather than a panel count derived from a photograph.
Assess the building structure, mounting system and panel model together. A module load test does not validate every mounting component. Ask who provides calculations and how edges, penetrations, service access and roof-snow hazards are handled.
Examine equipment availability, access conditions and work sequencing. Compare travel charges and service after an alert. A local company may know comparable sites; still request references and the service promised for your address.
Request monthly generation with horizon and snow-cover assumptions. For backup, define circuits and complete-system limits. A quote showing strong winter generation does not guarantee heating during a grid outage. Choose using plans, scope and proposed tests without turning a favourable scenario into a certain commitment.