Heat Pump, 2000l Storage Tank and Thermal Panels
A combination of different heating and cooling methods significantly lowered the running costs for this 1960s Milanese building.

Located in the centre of Milan, the 1960s building consists of 36 flats covering a total of 4500 m2. The air-conditioning system was based on two old boilers for heating and domestic hot water respectively, a chiller for cooling and distribution with radiators and fancoils.
Challenge:
In 2023 the condominium assembly decides to proceed with the energy requalification in order to reduce running costs, by intervening on the existing air-conditioning system.
The most important cost item to work on is that for Domestic Hot Water (DHW) production.
The solution chosen to cut down the cost for domestic hot water production is a system based on 1 high-efficiency heat pump with inverter technology and ecological refrigerant R32 Sheen EVO 2.0 combined with a 2000 litre storage tank and thermal solar panels, plus a condensing boiler that acts as a back-up during peak demand.
Lessons learned
The heat pump system combined with storage tank and thermal solar panels has proved to be an excellent solution for improving the building’s energy efficiency and cut down the costs for domestic hot water production.
Key facts
Building | Heat Pump and Source | ||
Location | Milan, Italy | Number of HP | 1 |
Construction | 1960 | Installed power | 93 kW |
Refurbishment | 2024 | Operation mode | hybrid |
Heat distribution | radiators, fancoils | Heat source | ambient air |
Heated area | 4500 m² | Type of system | Central |
No. of apartments | 36 | Model | Sheen EVO 2.0 heat pumps |
level of insulation | – | ||
Heating sytem | Domestic Hot Water | ||
Heat demand | – kWh / (m²a) | DHW demand | – kWh / (m²a) |
Heating temperature | -°C | Max. temperature | 70°C |
Via | Gas boiler 2 x 195kW | Circulation system | – |
Type | centralized system | ||
Additional heating | ST panels back-up boiler | ||
Other information | |||
PV installed | yes | COP | – |
Climate Zone | Cfa | Refrigerant | R32 |

Description of the technical concept
The central heat pump is sourced by ambient air and is turn connected to a 2000l storage unit. This storage unit is also connected to solar panels on the roof and – as a back-up – can be fed by a gas boiler (200kW). It distributes DHW to the 36 apartments in the building. Space Heating is provided by another gas boiler via heat exchangers.
Cooling is also possible through means of ambient air, a chiller and a storage unit.
IT009 Via Baldissera