1. Define the quoted project
Request kWp capacity, equipment models, layout, simulated generation and included work. Distinguish roof-mounted panels from an integrated roof: functions and construction scope differ. Compare options for the same building, specifying what each retains or replaces. A module price alone is not the installed project price.
2. Add building-related costs
Price access, scaffolding, structural work, waterproofing, electrical work, connection and commissioning as needed. Specify VAT, removal, coordination and exclusions. Separate roof renovation, battery, charger and backup. Agree a contingency for uncertain work with the contractors rather than adding one uniform percentage for every home.
3. Identify the Pronovo programme
Pronovo offers a one-off grant for small systems (PRU) below 100 kW, a one-off grant for large systems (GRU) from 100 kW and a higher one-off grant (RUE) for certain systems without self-consumption from 2 to 149.99 kW. Check capacity, type, commissioning date, any bonuses and the relevant procedure. Use the official calculator and keep its inputs. A quote percentage or installer label does not confirm the award amount.
4. Check other grants and tax treatment
Check canton and municipal programmes for your work, including rules for combining grants, dates and documents. Confirm tax-eligible expenses and grants to subtract for the building, canton and year. A taxable-income deduction is not an equivalent refund of the invoice. Show tax effects separately without promising one reduction rate for every owner.
5. Plan cash flow over time
List deposits, invoices, applications, decisions and expected payments. Identify who prepares and files each application with your authorisation. Compare cash, borrowing and third-party contracts using fees, interest, security and exit terms. The estimated final net cost does not by itself establish the funds needed when work begins.
6. Compare future costs and benefits
Separate electricity used on site, sold surplus and remaining purchases. Apply actual avoided prices and the feed-in contract to the corresponding flows. Add maintenance, insurance, finance and planned replacements. Compare a no-battery option and less favourable assumptions. Dividing initial cost by one year’s savings gives a simple indicator, not a lifetime return guarantee.