Before a new deadline or final invoice, document the condition of the site, missing deliverables and written responsibilities. Check the site data and official sources before signing.
Decision to make
Before a new deadline or final invoice, document the condition of the site, missing deliverables and written responsibilities. Adapt this decision to the building, your actual consumption and the project schedule.
For this project, start by identifying the grid operator, applicable tariff and site constraints. The quotation must specify the conditions affecting connection, metering or the value of surplus electricity.
Practical effects of the project
- A delay must be transformed into a written inventory: material delivered, work carried out, procedures accepted, missing tests and realistic date for the next stage.
- Separate material delays, roofing problems, refusal or study of the DSO, failure to install and simple absence of an appointment; the contractual response is not the same.
- Before paying the balance, ask for the deliverables that condition acceptance: commissioning, reports, connection, adjustments, guarantees and subsidy documents.
- A new date is only useful if it indicates responsibility, dependency, expected proof and consequence if not met.
- Do not withhold or unilaterally terminate any amount without re-reading the contract and, if necessary, seeking legal advice tailored to your case.
These points help assess the topic ‘ Late solar installation: what to ask before paying the balance ’ without turning a national average into a local promise. Every decisive figure needs its source, date and scope.
Specific controls
- Dated table of work, documents, dependencies and amounts already paid.
- Written decision from the DSO or proof of the approach if the network blocks the schedule.
- Timeline linked to deliverables, not just a promised date.
- Balance and receipt processed according to the contract; independent advice in the event of a dispute.
The answers should appear in the quote or in a dated appendix. A verbal explanation is insufficient if it changes the price, expected output, financial support or a contractual obligation.
Compare quotes
- Tariffs: state the purchase price, surplus remuneration and fixed charges applicable to the site, with their source and date.
- Production: provide a monthly estimate with orientation, shading, losses and weather assumptions.
- Investment: separate material, installation, safety, scaffolding, connection, procedures and options.
- Aids: distinguish confirmed amount, estimate and deposit liability.
- Contract: specify guarantees, calendar, deposit, exclusions, maintenance and after-sales service.
Before a new deadline or final invoice, document the condition of the site, missing deliverables and written responsibilities. In the comparison table, keep one column for the stated value, one for the evidence provided, and one for the effect of a less favorable hypothesis.
Cautious scenario
Test the project with slightly lower production, an unconfirmed grant and less favourable surplus remuneration. This scenario shows whether the decision remains sound based on self-consumption, roof quality and a controlled installed cost.
The main references used are SFOE - permits and low-voltage installations, Pronovo - Submit a photovoltaic subsidy application, OFEN/BFE - Connection conditions and remuneration 2026, Swissolar - Swiss Solar Monitor. They frame the method, but the local amounts and contractual conditions must be rechecked at the time the offer is signed.
Risks to be managed
Do not withhold or unilaterally terminate any amount without re-reading the contract and, if necessary, seeking legal advice tailored to your case. Ask who assumes this risk, what proof will be provided and how a change is handled after ordering.
A more expensive solution should meet a specific need in your project. Ask for a documented benefit and a separate price for each option.
Next step
Gather the address, annual consumption, future electricity uses and building documents. Then check the grid operator's conditions, available grants and site constraints; request quotations covering the same scope.
Before a new deadline or final invoice, document the condition of the site, missing deliverables and written responsibilities. You can then decide with a documented net price, clear responsibilities and assumptions that each company can explain line by line.
Points to check
- Tariffs: Compare the tariff for your address with the Swiss ElCom median for 2026, keeping local prices separate from the national benchmark.
- Grants: Check the programme, eligibility, documents and deadlines with Pronovo, the canton or municipality. Include only confirmed contributions in your budget.
- Roof potential: Sonnendach is presented as a public pre-diagnosis, to be validated by a technical visit.
- ROI: the method separates self-consumption, injection, installed price, taxation and payment schedule.
- A delay must be transformed into a written inventory: material delivered, work carried out, procedures accepted, missing tests and realistic date for the next stage.
- Separate material delays, roofing problems, refusal or study of the DSO, failure to install and simple absence of an appointment; the contractual response is not the same.