St Joseph's Care Home is quoted to save £16,123 in its first year from a 67.34 kWp rooftop solar system designed by Spirit Energy. The system is forecast to generate 57,727 kWh a year, covering roughly 32% of the home's electricity use. At a 22% internal rate of return and a five year payback, it sits inside the range Spirit Energy has modelled across its wider care home portfolio.
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.
