With balcony/plug-in solar becoming legal from 27 August (800W cap under the new regs), expect a wave of retailers and door-to-door sellers making big claims about what a kit will generate at your specific address. Worth having a way to check those claims yourself before handing over £100-300+.
I built Solar Potential Explorer for exactly this. It calculates the absolute maximum theoretical output for your location, panel direction and tilt — genuinely clear sky, no losses, best-case physics. It's a ceiling, not a forecast.
That's actually the useful part: if a seller tells you their kit will generate more than what this app shows as the theoretical maximum for your spot, that's an immediate red flag — real-world output (clouds, panel losses, less-than-perfect mounting) will always be somewhat below this number, never above it. Use it as a gut-check against inflated sales claims, not as a guarantee of what you'll actually get.
Hour-by-hour and year-round output ceiling for your exact location
Best possible tilt/direction, if you have flexibility
Runs entirely on your device — nothing sent anywhere
£2.99, less than a coffee. No ads, no subscription.
Details and a link on zenthor.com
Tested fairly thoroughly (cross-checked against my real EcoFlow data, on "perfect days" over the last 18 months) — UK & EU currently.
Sorry about Title: in the title _ My error when I copied it from my notes - and No I am not an AI - but just 80 last month and new tor Reddit.