Repair costs depend on the fault and the size of the unit. A battery replacement typically runs $150–$300. Transfer switch repair generally falls in the $250–$600 range. More complex repairs — control boards, engine components, or fuel system work — can run $500–$1,500 or more, and the larger 22kW+ units common on Indian Wells estates tend to fall toward the higher end of these ranges simply because the components are bigger. We diagnose first and provide a written estimate before any work begins, so there are no surprises.