The project
The owners of this certified passive house in Mersch wanted to complement their home's exceptional thermal performance with an energy production and storage system matching their environmental commitment.
The challenge
A passive house consumes very little energy (under 15 kWh/m²/year for heating). The system had to be precisely sized to avoid over-engineering, while covering domestic electricity needs, the mechanical ventilation system and heat pump.
Our solution
- Solar panels — 16 Jinko Solar Tiger Neo 440W modules (7.04 kWp) in roof-integrated mounting, due south orientation, 35° tilt
- Hybrid inverter — SMA Sunny Boy Storage 5.0 managing PV production and battery storage simultaneously
- Battery — BYD HVS 12.8 kWh, sized to cover 2 days of autonomy in mid-season
- Smart home — Integration with the existing home automation system (KNX) via SMA Sunny Home Manager 2.0
The deliberate oversizing of the battery relative to consumption enables extended periods of full autonomy in spring and summer.
Results
- Estimated annual production: 6,700 kWh
- Total annual consumption: 4,200 kWh (passive house)
- Self-consumption rate: 91%
- Self-sufficiency: 88% — near-autonomous from April to September
- Residual bill: under €80 per year of grid electricity purchased
- Surplus exported: ~1,500 kWh/year sold back to the supplier