Notes

A solar payback calculator for a panel installer, built on Phox Calculator Builder in formula mode with every result line hidden. System size, generation, the share used at home, the yearly saving, the fitted cost and the payback year feed each other in order, and Phox Calculator Value elements show the payback as an oversized numeral with three figures under it. Change a result name in the builder and the matching Calculator Value together, and keep each fallback close to the default result so the first paint is right. The radio options drop to one column on small phones, and number and half-width fields go full width at 768px and below.