A Saturday afternoon rings with the sound of a commercial promoting photovoltaic, or solar, installations. Salespeople often pitch these systems as self-financed through energy savings, with a "loan that pays itself back" through the electricity generated by the panels. But for many homeowners, this promise fades over time. Years later, the original seller may have vanished, the solar installation may no longer function, and the monthly payment from their bank account continues without interruption. This situation is becoming increasingly common, as individuals are often visited at home by salespeople who push for quick decisions, with contracts signed the same day alongside a loan from a partner institution. There's little time to reflect or compare with other professionals—just a signature, often slipped in between a coffee and the cooling of another. The residential inverter, a key component that converts the direct current from solar panels into usable electricity, typically fails between 10 to 12 years. This is well before the loan, which can last up to 15 to 20 years, is fully repaid. Even if the sales contract is canceled, the loan itself is not automatically canceled, leaving the bank as the creditor. To avoid many of these issues, consumers are advised to check the decennial insurance, which covers the installation for ten years, the RGE certification (a quality assurance mark for energy-efficient work), and the age of the company. These checks can prevent 90% of future problems. However, the decennial guarantee only applies to solar panels if they contribute to the building’s structural integrity or waterproofing. In many cases, the promised energy yield never matches the sales pitch, and issues like delayed connections, faulty installations, or unexamined roof structures can quickly follow. Homeowners who sign up for solar panels are often promised quick profitability, energy savings, and government aid, all funded by a loan that seems like a formality. But soon, problems arise: delays in installation, connection failures, component breakdowns, and a lack of after-sales support. The inverter, the most fragile part of the system, is usually the weak link. It generally lasts 10 to 12 years, depending on the quality of the components and thermal conditions, not the amount of electricity produced. This means that the key part of the system may fail long before the loan is paid off. Yet, the monthly payments continue as if nothing has changed. The result is a roof that produces no electricity, while the automatic debit continues for years. A common misconception is that if the seller goes bankrupt, the loan is also canceled. This is not true. Even if the sales contract is canceled due to formal irregularities, the borrower is still obligated to repay the bank. However, if the bank failed to verify the legality of the contract before disbursing the loan, it could be held responsible. Legal precedents have shown that when the lender disburse funds without checking the proper documentation, the burden of repayment may fall on the bank, especially if the installer becomes insolvent. In a recent case, the appellate court of Rouen ruled that a pre-printed mention of a brand followed by "or equivalent" was not sufficient, and the absence of the specific panel brand led to the contract being declared invalid. These administrative details can have major legal consequences. To protect themselves before signing, consumers should perform three key checks. First, verify that the installer has a valid decennial insurance policy, which remains effective for ten years after the work is completed, even if the company goes bankrupt. Second, check the age of the company and look for verifiable customer references and a physical address. Lastly, never sign a contract during the salesperson’s visit. Always request the RGE certification and verify it on the official website. Comparing at least two quotes over several days can also help identify overly optimistic production estimates. It’s also important to understand that the decennial guarantee does not cover everything—it applies only if the solar panels contribute to the building’s structural integrity or waterproofing. This technical detail often becomes a legal barrier when problems arise and the installer is no longer reachable.