Motivation
The existing heat pump provided no native interface for monitoring or external control. To enable data logging, performance evaluation and better utilization of self-produced photovoltaic energy, a Home Assistant integration was developed.
Communication with the heat pump controller is realized via its Modbus interface, based on available documentation and additional reverse engineering.
System Design
The heat pump controller is connected to Home Assistant via Modbus. Relevant registers are read cyclically and exposed as sensors, providing access to temperatures, operating states and electrical power consumption. Selected parameters are writable to allow controlled interaction with the system.
To enable accurate thermal performance analysis, an ultrasonic flow sensor at the heat pump output is planned. This will allow calculation of live COP values and long-term SPF metrics.
The required flow sensor has been kindly provided free of charge by Sciosense. At the time of writing, delivery is still pending.
Control & Measurement
The integration is already fully operational for monitoring and basic control via Home Assistant. Once the flow sensor is installed, thermal output power, COP and SPF will be calculated automatically using electrical and hydraulic measurement data.
Project Status
The project is ongoing. Core integration is complete and in daily use; performance measurement will be extended once the flow sensor becomes available. Updates will follow.
Lessons Learned
- Legacy heat pump systems often expose powerful interfaces suitable for modern integration.
- Meaningful efficiency analysis requires both electrical and flow measurements.
- Incremental development allows productive use while the project is still evolving.