May 30, 2026
Sun, scandal, and postcode snooping
Show HN: Helios – what plug-in solar could generate for any address in Britain
Brits are already plotting balcony power — and arguing over whether the numbers are too neat
TLDR: Helios shows Brits how much electricity plug-in balcony solar could generate at their address, using public map data and without storing addresses. Commenters loved the idea but quickly split into two camps: people asking for more features, and skeptics warning that precise-looking estimates can be misleading if the location data is shaky.
The big news is simple: plug-in solar is about to land in the UK, which means some people may soon be able to stick solar panels on a balcony and make their own electricity without the usual expensive installation drama. Helios leans hard into that dream by letting you type in a British address and get a rough idea of how much power you could make. It says it checks the shape of nearby buildings, uses public height-scan data, and doesn’t save your address — a privacy-friendly detail that earned quiet approval.
But the real action was in the crowd reaction, where people instantly turned from "cool!" to "okay, but what about my oddly shaped street?" One commenter loved it so much they immediately asked for normal rooftop solar too, which is basically the internet version of saying, "Nice app, now make it bigger." Another was having a full-on "today I learned" moment over the UK’s public mapping and laser-scan data, praising the country’s open data scene like a proud parent at sports day.
Then came the classic comment-thread tension: is the tool a little too confident? One user warned that if the site can’t properly find your exact building, it may still spit out very precise-looking shade estimates, creating what amounts to suspiciously fancy guesswork. Meanwhile, others were already trying to turn Helios into a shopping companion for house-hunters or asking for a compass picker so they could test the front garden vs back garden solar showdown. In other words: part excitement, part feature wishlist, part polite nerd battle over whether the map is genius or giving off fake-certainty vibes.
Key Points
- •The article presents Helios as a tool for estimating plug-in solar electricity generation for specific addresses in Britain.
- •It says plug-in solar panels will be available in the UK soon and can be installed on balconies without expensive installation fees or planning permission.
- •Users enter a postcode and house or flat number to see estimated energy generation and whether the system is likely to be worth it.
- •The calculation uses Ordnance Survey data to resolve addresses and Environment Agency LIDAR data to model shading from surrounding buildings.
- •Annual yield is estimated with PVGIS, and the article states that user addresses are not stored.