Calculators for the obvious money questions

Each one prints every step it takes to reach the number. Built for sanity-checking quotes, not for marketing.

Solar

Payback estimator

Roof orientation, shading, tariff and behaviour. Year-by-year breakdown.

Uses: roof orientation, shading, install cost, tariff

Battery

Smallest battery that catches most of your spare solar.

Uses: evening load shape, export pattern, round-trip losses

EV charging

Smart-tariff overnight charging compared to standard rates.

Uses: annual mileage, vehicle efficiency, tariff windows

Heat pumps

Back-of-envelope sanity check on the survey figure quoted.

Uses: floor area, insulation level, target room temperature