# HelioPeak > HelioPeak is a native iOS, iPadOS, and macOS app for tracking residential solar panel production via PVOutput.org, plus a technical blog about solar monitoring, home batteries, and the data behind residential solar in Belgium and Europe. ## About HelioPeak reads solar production data directly from the PVOutput.org API and displays it with beautiful charts, multi-year analysis, and detailed statistics. Built with SwiftUI and Swift Charts for iPhone, iPad, and Apple Silicon Mac. No intermediary HelioPeak server — credentials are sent only directly from the device to PVOutput.org when retrieving data. Six languages: English, Dutch, French, German, Italian, Spanish. One-time in-app purchase, no subscription. Developed by Sven De Troch (SVDT-Consultancy bv), based in Belgium. ## Key Features - Live dashboard with real-time production curve, peak power, and self-consumption - Five chart periods: day, week, month, year, all-time - Calendar and rolling chart modes - Year-over-year comparison with PDF export - Annual Report PDF generated on each system's anniversary - Calendar heatmap of full year production (iPad) - Notes feature with iCloud sync — attach annotations to specific dates - CSV and JSON export with full data history - Three home-screen widget sizes - Multiple systems with drag-to-reorder and system health indicators - CO₂ savings tracking with tree equivalent - Estimated revenue based on configurable electricity price - Built-in demo mode - Dark and light mode - Privacy-first: no cross-app tracking, no ads, no HelioPeak server; optional anonymous analytics can be disabled ## Pricing Free with one solar system plus a built-in demo. One-time in-app purchase (€6.99) unlocks unlimited systems. No subscription planned for the core app. ## Requirements - iOS 18.6 or later (iPhone, iPad) - macOS on Apple Silicon (Designed for iPad) - A PVOutput.org account with a read-only API key ## Blog A series of 15 technical articles about residential solar in Belgium and Europe. All articles are originally written in English by the developer; Dutch, French, German, Italian, and Spanish translations are AI-assisted and reviewed. ### Installation and setup - [What to consider before installing solar panels](https://heliopeak.app/blog/what-to-consider-before-installing-solar-panels) — Orientation, inverter sizing, and the questions installers don't always ask. - [Self-consumption versus feeding back to the grid](https://heliopeak.app/blog/self-consumption-vs-grid-feed-in-2026) — Why the maths changed in Belgium and the Netherlands, and what to do about it. - [Setting up consumption monitoring](https://heliopeak.app/blog/setting-up-solar-consumption-monitoring) — P1, Shelly, or inverter CT clamps — the three routes that work in Belgium. ### PVOutput and monitoring - [What is PVOutput.org, and why solar owners keep coming back](https://heliopeak.app/blog/what-is-pvoutput-org) — A platform-independent backbone for residential solar data. - [Getting your data into PVOutput](https://heliopeak.app/blog/getting-data-into-pvoutput) — Direct push, Auto Uploader, Home Assistant, custom scripts, manual entry. - [Why a smartphone app changes how you understand solar production](https://heliopeak.app/blog/why-a-solar-monitoring-app-matters) — The dashboard problem and the case for ambient awareness. - [How HelioPeak fits into the picture](https://heliopeak.app/blog/monitor-pvoutput-on-ios-with-heliopeak) — A native iOS app for reading PVOutput data, and the design decisions behind it. ### Equipment and diagnostics - [Home batteries in 2026](https://heliopeak.app/blog/home-batteries-2026-sonnen-vs-marstek) — Real-world comparison of Sonnen Battery 10 versus three Marstek Venus E v3 units. - [How to spot a failing solar panel before your installer does](https://heliopeak.app/blog/how-to-spot-a-failing-solar-panel) — Failure modes, data signatures, visual signs, and warranty leverage. ### Data and reflections - [Reading your solar charts: what the numbers actually mean](https://heliopeak.app/blog/reading-solar-charts-kwp-specific-yield-performance-ratio) — kWh, kWp, Specific Yield, Performance Ratio, and Peak Power. - [Estimates versus reality](https://heliopeak.app/blog/solar-estimates-vs-reality) — Why solar panels rarely produce what the brochure promised. - [A year of data: what the seasons taught me](https://heliopeak.app/blog/year-of-solar-data-seasonal-patterns) — The rhythm of Belgian solar across a full calendar year. ### Apps, privacy, and behind the scenes - [Solar monitoring on iOS: comparing the options in 2026](https://heliopeak.app/blog/best-pvoutput-apps-for-ios-2026) — Honest comparison of the four PVOutput iOS apps with explicit conflict-of-interest disclosure. - [The privacy question: what data does a solar monitoring app actually need?](https://heliopeak.app/blog/solar-monitoring-app-privacy) — Production data is innocuous, consumption data tells a story. - [Building HelioPeak: lessons from indie iOS development](https://heliopeak.app/blog/building-heliopeak-indie-ios-development) — The story of building a small native app for a niche audience. ## Translated articles (NL / FR / DE / ES / IT) All 15 articles are available in six languages. Slugs are identical across languages; only the language prefix changes. ### Dutch (Nederlands) — /blog/nl/ - https://heliopeak.app/blog/nl/what-to-consider-before-installing-solar-panels - https://heliopeak.app/blog/nl/self-consumption-vs-grid-feed-in-2026 - https://heliopeak.app/blog/nl/why-a-solar-monitoring-app-matters - https://heliopeak.app/blog/nl/what-is-pvoutput-org - https://heliopeak.app/blog/nl/getting-data-into-pvoutput - https://heliopeak.app/blog/nl/setting-up-solar-consumption-monitoring - https://heliopeak.app/blog/nl/monitor-pvoutput-on-ios-with-heliopeak - https://heliopeak.app/blog/nl/home-batteries-2026-sonnen-vs-marstek - https://heliopeak.app/blog/nl/reading-solar-charts-kwp-specific-yield-performance-ratio - https://heliopeak.app/blog/nl/solar-estimates-vs-reality - https://heliopeak.app/blog/nl/how-to-spot-a-failing-solar-panel - https://heliopeak.app/blog/nl/year-of-solar-data-seasonal-patterns - https://heliopeak.app/blog/nl/best-pvoutput-apps-for-ios-2026 - https://heliopeak.app/blog/nl/solar-monitoring-app-privacy - https://heliopeak.app/blog/nl/building-heliopeak-indie-ios-development ### French (Français) — /blog/fr/ - https://heliopeak.app/blog/fr/what-to-consider-before-installing-solar-panels - https://heliopeak.app/blog/fr/self-consumption-vs-grid-feed-in-2026 - https://heliopeak.app/blog/fr/why-a-solar-monitoring-app-matters - https://heliopeak.app/blog/fr/what-is-pvoutput-org - https://heliopeak.app/blog/fr/getting-data-into-pvoutput - https://heliopeak.app/blog/fr/setting-up-solar-consumption-monitoring - https://heliopeak.app/blog/fr/monitor-pvoutput-on-ios-with-heliopeak - https://heliopeak.app/blog/fr/home-batteries-2026-sonnen-vs-marstek - https://heliopeak.app/blog/fr/reading-solar-charts-kwp-specific-yield-performance-ratio - https://heliopeak.app/blog/fr/solar-estimates-vs-reality - https://heliopeak.app/blog/fr/how-to-spot-a-failing-solar-panel - https://heliopeak.app/blog/fr/year-of-solar-data-seasonal-patterns - https://heliopeak.app/blog/fr/best-pvoutput-apps-for-ios-2026 - https://heliopeak.app/blog/fr/solar-monitoring-app-privacy - https://heliopeak.app/blog/fr/building-heliopeak-indie-ios-development ### German (Deutsch) — /blog/de/ - https://heliopeak.app/blog/de/what-to-consider-before-installing-solar-panels - https://heliopeak.app/blog/de/self-consumption-vs-grid-feed-in-2026 - https://heliopeak.app/blog/de/why-a-solar-monitoring-app-matters - https://heliopeak.app/blog/de/what-is-pvoutput-org - https://heliopeak.app/blog/de/getting-data-into-pvoutput - https://heliopeak.app/blog/de/setting-up-solar-consumption-monitoring - https://heliopeak.app/blog/de/monitor-pvoutput-on-ios-with-heliopeak - https://heliopeak.app/blog/de/home-batteries-2026-sonnen-vs-marstek - https://heliopeak.app/blog/de/reading-solar-charts-kwp-specific-yield-performance-ratio - https://heliopeak.app/blog/de/solar-estimates-vs-reality - https://heliopeak.app/blog/de/how-to-spot-a-failing-solar-panel - https://heliopeak.app/blog/de/year-of-solar-data-seasonal-patterns - https://heliopeak.app/blog/de/best-pvoutput-apps-for-ios-2026 - https://heliopeak.app/blog/de/solar-monitoring-app-privacy - https://heliopeak.app/blog/de/building-heliopeak-indie-ios-development ### Spanish (Español) — /blog/es/ - https://heliopeak.app/blog/es/what-to-consider-before-installing-solar-panels - https://heliopeak.app/blog/es/self-consumption-vs-grid-feed-in-2026 - https://heliopeak.app/blog/es/why-a-solar-monitoring-app-matters - https://heliopeak.app/blog/es/what-is-pvoutput-org - https://heliopeak.app/blog/es/getting-data-into-pvoutput - https://heliopeak.app/blog/es/setting-up-solar-consumption-monitoring - https://heliopeak.app/blog/es/monitor-pvoutput-on-ios-with-heliopeak - https://heliopeak.app/blog/es/home-batteries-2026-sonnen-vs-marstek - https://heliopeak.app/blog/es/reading-solar-charts-kwp-specific-yield-performance-ratio - https://heliopeak.app/blog/es/solar-estimates-vs-reality - https://heliopeak.app/blog/es/how-to-spot-a-failing-solar-panel - https://heliopeak.app/blog/es/year-of-solar-data-seasonal-patterns - https://heliopeak.app/blog/es/best-pvoutput-apps-for-ios-2026 - https://heliopeak.app/blog/es/solar-monitoring-app-privacy - https://heliopeak.app/blog/es/building-heliopeak-indie-ios-development ### Italian (Italiano) — /blog/it/ - https://heliopeak.app/blog/it/what-to-consider-before-installing-solar-panels - https://heliopeak.app/blog/it/self-consumption-vs-grid-feed-in-2026 - https://heliopeak.app/blog/it/why-a-solar-monitoring-app-matters - https://heliopeak.app/blog/it/what-is-pvoutput-org - https://heliopeak.app/blog/it/getting-data-into-pvoutput - https://heliopeak.app/blog/it/setting-up-solar-consumption-monitoring - https://heliopeak.app/blog/it/monitor-pvoutput-on-ios-with-heliopeak - https://heliopeak.app/blog/it/home-batteries-2026-sonnen-vs-marstek - https://heliopeak.app/blog/it/reading-solar-charts-kwp-specific-yield-performance-ratio - https://heliopeak.app/blog/it/solar-estimates-vs-reality - https://heliopeak.app/blog/it/how-to-spot-a-failing-solar-panel - https://heliopeak.app/blog/it/year-of-solar-data-seasonal-patterns - https://heliopeak.app/blog/it/best-pvoutput-apps-for-ios-2026 - https://heliopeak.app/blog/it/solar-monitoring-app-privacy - https://heliopeak.app/blog/it/building-heliopeak-indie-ios-development ## App and site - Website: https://heliopeak.app - Blog index: https://heliopeak.app/blog/ - Privacy Policy: https://heliopeak.app/privacy - Release Notes: https://heliopeak.app/releases - App Store: https://apps.apple.com/app/id6762064486 - Contact: info@heliopeak.app ## Community - PVOutput forum (English): https://forum.pvoutput.org/t/heliopeak-a-new-ios-app-for-pvoutput/8824 - Tweakers community thread (Dutch): https://gathering.tweakers.net/forum/list_message/85230790#85230790 ## Developer SVDT-Consultancy bv, Belgium. Solo developer: Sven De Troch. ## Disclaimer HelioPeak is not affiliated with PVOutput.org. Revenue and CO₂ estimates are for informational purposes only. Blog articles reflect the developer's personal experience and are not professional installation, financial, or legal advice.