Shade reduces solar output in steps rather than gradually, because a single shaded cell on a standard panel can switch off a third of it. On most UK homes the cheapest fixes are design decisions that cost nothing: mounting panels to suit the direction the shadow runs, and putting shaded panels on their own inverter input. During testing, micro inverters recovered 40 to 50% of the output lost to shade, so they are worth fitting only when that extra generation pays back comfortably inside the warranty period.
