01
Location and geometry
Broad solar resource varies across Wales, while orientation and inclination influence the array’s yearly profile. East-west layouts can trade peak output for a wider generation window.
02
Local shading
Topography, trees, chimneys and neighbouring buildings can matter. The assessment should model the timing and electrical impact of shade, not just label the roof sunny or shaded.
03
Request the inputs
Ask for array kWp, site irradiation or regional factor, orientation, inclination, shading and loss assumptions behind the annual kWh figure.