openenergymonitor.org

What It Is

OpenEnergyMonitor is an open-source monitoring system for electricity, solar, energy storage, and heat pumps. Launched in 2009, the project aims to help users understand energy usage and the performance of zero-carbon energy systems through open hardware and software. It is not simply a software development tool, but a complete energy data collection and visualization solution made up of sensor nodes, Raspberry Pi/Arduino platforms, and the EmonCMS data platform.

Core Capabilities

According to the main content, the core hardware includes emonPi3, emonTx6, and emonTH2. emonPi3 is a six-channel electricity monitor with an integrated Raspberry Pi. It supports single-phase or three-phase monitoring, wired temperature sensing, and pulse counting, and can also act as a base station for other sensor nodes. emonTx6 is used to expand additional CT inputs, making it suitable for adding monitoring points in the same location or other areas of a building. emonTH2 is designed for room-level wireless temperature and humidity collection. Data is recorded and visualized locally or remotely through EmonCMS, which supports preset dashboards, charting tools, and flexible input processing.

Open Source, Self-Hosting, and Ecosystem

The project clearly states that both its hardware and software are open source, which is its biggest distinguishing feature. The documentation covers emonSD, emonHub, EmonCMS, MQTT, CSV export, remote access, backup and restore, and more, indicating that the system can run locally on emonPi3 or connect to the remote EmonCMS.org service, with strong self-hosting potential. The ecosystem also includes EmonEVSE, HeatpumpMonitor.org, and solar and heat pump applications, making it suitable for long-term expansion.

Pricing

The main content only states that all products can be purchased from the Shop. It does not disclose specific prices, nor does it state whether remote EmonCMS.org usage is paid. Therefore, its business model can only be understood as open-source software combined with hardware sales.

Pros and Cons

The advantages are its open and transparent nature, detailed documentation, modular hardware, support for local data control, and coverage of practical scenarios such as home energy and heat pumps. The drawbacks are a relatively high deployment barrier: users need to understand electricity monitoring, sensor installation, and system configuration. Pricing, payment methods, and purchase support for users in China are not reflected in the main content.

Who It’s For and Access from China

It is suitable for DIY energy monitoring users, heat pump/PV system owners, energy researchers, and technical teams that want to self-host their data. There is no evidence in the main content regarding access from China, so it is rated as unknown. If hardware purchases are involved, logistics, electrical standards, and compliance with the 433.92MHz wireless frequency band also need to be confirmed separately.