Changelog

During winter operation (ambient temperatures below 0 °C), the ground source heat pump consistently consumed over 50 kWh per day. This level of consumption had a noticeable impact on the electricity bill and was not aligned with: the building's actual heat demand, the thermal inertia of the ground loop, or efficient compressor operation. The system was running on mostly default, conservative settings with no fine-grained control over priorities and schedules.

The configuration changes were applied on January 26. This section evaluates their impact using real electricity consumption data and outdoor temperature data from the heat pump itself, ensuring consistent and comparable measurements. Raw Consumption Overview (Timeline) Daily electricity consumption data from SolarEdge shows: January (before optimization): Typical daily consumption: 45-55 kWh Multiple days exceeding 50 kWh, even at moderate winter temperatures Late January (immediately after optimization): Short-term reduction in daily consumption Several days in the 40-45 kWh range February (after optimization, very cold period): Daily consumption often again exceeded 50 kWh This coincided with significantly lower outdoor temperatures, including periods below -10°C and down to approximately -15°C 📈 Consumption timeline (SolarEdge): consumption January consumption February Weather Context Outdoor temperature data used in this analysis comes directly from the outdoor temperature sensor

The off-grid backup system could not operate reliably during real grid outages and power failures. When a grid loss occurred: The SolarEdge Backup system attempted to transition into off-grid mode At the same time, the heat pump was free to start according to its internal logic Compressor startup caused a high inrush power demand The inverter and battery could not supply this peak instantly As a result: The off-grid transition failed or became unstable Inverter protection mechanisms were triggered Backup operation required manual intervention To keep the system running during a power outage, the heat pump had to be manually enabled or disabled at the right moment. In practice: Off-grid operation during a grid failure depended on human action. This led to: No reliable automatic behavior during outages High risk of incorrect timing under stress Reduced system resilience exactly when backup power was needed most The setup worked under normal conditions, but failed precisely during grid fa

After introducing SG Ready-based control using the SolarEdge Home Load Controller, the system now behaves predictably during real grid outages. Off-grid transitions are stable and repeatable The heat pump no longer starts during unsafe moments Backup operation works without manual intervention Startup power spikes no longer destabilize the inverter PV surplus is used only when conditions allow it The backup system now works automatically and reliably, exactly when the grid is unavailable.