The answer depends on the pump’s starting current, not only its running wattage. SRNE lists motor capacity of 5HP for the 8kW model and 6HP for the 12kW model, together with 2× short-duration output. If the pump is the dominant startup load, the 8kW inverter may already be sufficient when the measured inrush and simultaneous household demand remain inside its limits. The 12kW model adds more continuous and peak headroom, but it should be selected from a load schedule rather than simply choosing the larger rating.
