Option 1: own funds and available reserve
Using your own funds avoids loan interest, but reduces your available reserve. Compare estimated solar savings with other uses of the money and retain a contingency. An advertised return is not a guaranteed investment return.
Option 2: a mortgage increase for renovations
A bank may finance energy renovations through a mortgage increase or a specific product. UBS and Raiffeisen publish offers subject to their conditions. Ask about rates, term, fees, repayments and credit requirements; solar does not guarantee a rate below 2% or application approval.
Option 3: Private credit (consumer loan)
A personal loan can be an alternative depending on your circumstances. Compare effective interest, term, monthly payment and total cost with project savings. The lender assesses repayment capacity; neither approval nor a one-week turnaround is guaranteed.
Solar Contracting (Rental)
Under a contracting agreement, a third party finances or operates the system according to the contract. Check equipment ownership, electricity price, indexation, maintenance, insurance, term and purchase options. Distinguish roof rental from electricity supply: the rights and duties differ.