# Helios

> **TL;DR.** Helios is a free UK address-level calculator that answers one question: is plug-in solar worth it for your home? Enter a postcode, and it ray-traces the surrounding buildings using Environment Agency LIDAR data to estimate real shading, then queries the EU PVGIS API for an annual yield figure.

- **Category:** CleanTech / Consumer Tools / Energy
- **Stage:** nascent
- **Age:** 4 days
- **Origin date:** 2026-05-30
- **First detected:** 2026-05-30
- **Canonical URL:** https://earlyterms.com/term/helios
- **Sources:** 5 primary URLs

## Definition

Helios is a free UK address-level calculator that answers one question: is plug-in solar worth it for your home? Enter a postcode, and it ray-traces the surrounding buildings using Environment Agency LIDAR data to estimate real shading, then queries the EU PVGIS API for an annual yield figure.

South London Scientific's [Helios](https://helios.southlondonscientific.com/) launched on 30 May 2026 — days after BS 7671 Amendment 4 made 800 W plug-in solar kits legal in Britain on 15 April 2026. The tool accounts for your electricity tariff and the Smart Export Guarantee rules to output a personalised payback period and 20-year net saving.

## Analogy

Think of it as a sat-nav for sunlight — it checks what's in the way before telling you whether to bother.

## Why it's emerging now

Plug-in solar became legal in Great Britain on 15 April 2026 under BS 7671 Amendment 4, opening a renter-accessible solar market for the first time. Helios launched two weeks later as the first address-level feasibility tool that uses real LIDAR shading data — a gap no existing UK solar calculator had filled.

## Related terms

- *parent:* plug-in solar
- *related:* balcony solar
- *related:* PVGIS
- *related:* BS 7671
- *related:* Smart Export Guarantee
- *related:* LIDAR solar mapping
- *competitor:* HeliosHome
- *related:* Energy Performance Certificate
- *related:* Renters' Rights Act 2025

## Sources

1. [Helios — official tool (South London Scientific)](https://helios.southlondonscientific.com/)
2. [Show HN: Helios — what plug-in solar could generate for any address in Britain (77 pts)](https://news.ycombinator.com/item?id=48334949)
3. [UKEM Group: Plug-in solar legalised in UK — 800W from 15 April 2026](https://www.ukem.co.uk/solar-battery-storage/news/plug-in-solar-legalised-uk)
4. [Plug-in Solar Explained: UK regulations, kit requirements, and installation guide](https://www.pluginsolarexplained.co.uk/)
5. [PVGIS — European Commission photovoltaic yield API](https://joint-research-centre.ec.europa.eu/photovoltaic-geographical-information-system-pvgis_en)

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_Generated by EarlyTerms · https://earlyterms.com/term/helios_