Financial returns mainly come from avoided grid imports, rather than surplus sales. Check the site data and official sources before signing.
Decision to make
Financial returns mainly come from avoided grid imports, rather than surplus sales. 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
- Project returns depend on self-consumed electricity and exported surplus, valued at the applicable tariffs.
- The calculation must distinguish between energy, network, taxes, surplus recovery, taxation and aid payment schedule.
- A house with a heat pump, controllable boiler or electric car can generate much more production during the day.
- Confirm the applicable tariff with the grid operator when the quotation is prepared, since it can change the value of the same production.
- A good scenario compares at least three cases: no battery, battery prepared, battery installed.
These points help assess the topic ‘ Profitability of solar panels in Switzerland: the real calculation to be made ’ without turning a national average into a local promise. Every decisive figure needs its source, date and scope.
Specific controls
- Confirm site data with the relevant professionals and connection conditions with the grid operator.
- Show base price, options, connection, aid and exclusions separately.
- Compare a reference hypothesis with a conservative variant before signing.
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.
Financial returns mainly come from avoided grid imports, rather than surplus sales. 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 ElCom - Slight drop in electricity prices in 2026, Swissolar - Swiss Solar Monitor, SFOE - support for photovoltaic installations, Pronovo - Submit a photovoltaic subsidy application. 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
A good scenario compares at least three cases: no battery, battery prepared, battery installed. 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.
Financial returns mainly come from avoided grid imports, rather than surplus sales. You can then decide with a documented net price, clear responsibilities and assumptions that each company can explain line by line.
A financial example: comparing repair and expansion
An owner has a working installation and considers keeping it, replacing a component or adding modules in this illustrative case. Separate new investment from money already spent. Do not count the old purchase price again in the return on the extension alone.
For each option, separate extra generation, avoided purchases, exports and new costs. If a battery uses some of the same surplus, allocate flows without counting two savings for one kWh. Include servicing, losses, subscriptions and possible replacement.
Also present net present value and annual cash flow with the chosen financing assumptions. A short payback and low total cost need not identify the same option. Choose according to ownership horizon and accepted risks.
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.
- Project returns depend on self-consumed electricity and exported surplus, valued at the applicable tariffs.
- The calculation must distinguish between energy, network, taxes, surplus recovery, taxation and aid payment schedule.