Solar calculators
PV yield from real hourly satellite weather, payback, panel count, tilt, strings, off-grid.
Solar panel output & payback
Simulates every hour of a full year at your exact location using NASA satellite weather, then turns the energy into savings, payback time and CO₂ avoided.
live data SolarHow many solar panels?
Turns your yearly kWh (or monthly bill) into the number of panels, system size and roof area you need, using NASA satellite sunshine for your exact location, your panel model and roof orientation.
SolarBest solar panel angle
Finds the optimum tilt and orientation by simulating every hour of a real NASA weather year at 30+ panel angles. Includes seasonal angles, roof-pitch losses and an east/west comparison.
live data SolarPanels that fit on a roof
Lays out real modules on a pitched, gable or flat roof, with edge and ridge setbacks, obstructions, portrait, landscape or mixed rows and row spacing on flat roofs. You get the panel count, kWp, kWh per year and roof load.
SolarNet metering vs net billing
See what your solar exports are really worth: month-by-month netting, kWh or money credit rollover, year-end true-up, non-nettable network charges and fixed fees, side by side for every scheme.
SolarSolar inverter sizing
Simulates your array hour by hour with NASA weather to show how much energy each inverter size would clip, then recommends the size, the phase and the economic DC/AC ratio.
live data SolarPV string sizing
Checks a PV string against the inverter’s maximum DC voltage, MPPT window, start-up voltage and current limits at your record cold and hottest conditions, using the NEC 690.7 and IEC methods.
SolarSolar water heater sizing
Sizes a solar hot-water system with the f-chart method used by engineers, fed with NASA satellite climate for your location: monthly solar fraction, savings versus electric, gas or heat pump, and payback.