Commercial vs Residential Solar Panels Cost Calculator

How this calculator works

This calculator works in ranges rather than single figures, because real quotes, yields and tariffs genuinely vary that much. It starts from typical UK price, output and savings ranges drawn from published 2026 industry guides and official scheme documentation, then scales them by the quantities you enter and adjusts them for each choice you make below. The result is a low-to-high band that a realistic outcome is likely to fall within, not a promise of the figure you will achieve.

Homeowners pay roughly to per kWp installed in 2026 while businesses pay roughly to per kWp for typical rooftop projects, so commercial solar costs 40 to 50 percent less per unit of capacity. The gap is scale, not different hardware: scaffolding, design, grid applications and installer overheads are similar whether the array is 4 kWp or 100 kWp, so bigger systems dilute them.

System size to compare (kWp)

Enter a system size to price both ways. The comparison is most meaningful at sizes both markets actually install, roughly 4 to 30 kWp, since few homes exceed 10 kWp and few businesses install below 10. At larger sizes the commercial advantage grows further as fixed costs dilute.

What else affects the figures

The two markets also differ beyond the headline price. Residential installations enjoy 0 percent VAT until March 2027 while commercial systems are quoted excluding 20 percent VAT, reclaimable for VAT-registered businesses; businesses can additionally claim the Annual Investment Allowance, deducting the full cost against year-one profits. Payback runs faster commercially too, typically 4 to 7 years against 8 to 11 domestically, because businesses consume most of their generation on-site at commercial rates. Homeowners cannot access commercial pricing directly, but the same logic argues for filling the roof in one visit rather than installing in stages.

Certification, planning and grid connection

Commercial rooftop solar often benefits from permitted development rights, but larger arrays, ground mounts, listed buildings and conservation settings can require planning permission, so early advice from the local planning authority is worthwhile. All grid-connected commercial systems need district network operator engagement, routine G98 notification for very small systems and a G99 application, occasionally with export limitation or reinforcement, for anything substantial. A structural assessment of the roof is standard practice, VAT applies at 20 percent but is reclaimable for VAT-registered businesses, and the Annual Investment Allowance typically allows the full cost to be set against year-one profits, which materially improves the investment case.