## Turn 1

The user wants to know the warranty duration for a residential customer based on the provided sources.

1.  **Analyze the question:** "What warranty applies to a residential customer?"
2.  **Scan the sources:**
    *   [S1] "The service warranty lasts 24 months for residential customers." -> This directly answers the question.
    *   [S2] "Commercial customers receive 12 months of warranty." -> Irrelevant to residential customers.
    *   [S3] "Batteries are excluded after 6 months." -> This is a specific exclusion, but the general warranty is defined in S1. The question asks generally what warranty applies. S1 is the primary answer.
3.  **Formulate the answer:** The warranty lasts 24 months.
4.  **Add citation:** [S1].

Final Answer: The service warranty lasts 24 months [S1].