Renovation of DHW production in twelve social dwellings
The DHW production was ensured by individual electric water heaters until now. The replacement of these by a collective heat pump induces a 50% reduction on the electric bill due to DHW production.

Lessons learned
- Before renovating, the primary energy consumption due to DHW production was about 75kWhep/m².yr.
- Final objective for ep consumption is 24 kWhep/m².yr.
Key facts
Building | Heat Pump and Source | ||
Location | Soisson, France | Number of HP | 1 |
Construction | retrofit | Installed power | 11kW |
Heat distribution | underfloor heating | Operation mode | monoenergetic |
Heated area | 841 m² | Heat source | ambient air |
No. of apartments | 12 | Function | DHW only |
level of insulation | – | Model | Atlantic |
Heating sytem | Domestic Hot Water | ||
Heat demand | – kWh / (m²a) | DHW demand | 29kWhep/m².yr. in 2013 |
Heating temperature | – °C | Type of system | central |
Heat supply | District Heating | Max. temperature | 65 °C |
Circulation system | yes (thermodynamic loop) | ||
Other information | |||
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Description of the technical concept

The system consists of:
- A 11kW Atlantic® air-to-water heat pump
- Two storage tanks with 750l capacity each
- An Atlantic® thermodynamic loop heater
The system functioning is based on an accumulated mode: the storage tanks allow to store the daily DHW needs. Then, the heat pump produces heat during the night, for eight hours continuously.
Even if the outside air temperatures are lower during the night, this type of operation offers advantages in terms of performances:
- After a day of draw-offs, the volume of water in the tanks is completely cold
-> optimized COP
- An operation during night allows to benefit from lower electricity tarrifs
FR005 Soisson