ECO-SANDWICH family house (3 apartments) in Koprivnica
nZEB Example

Building structure is a seismic resistant reinforced concrete frame. It has three stories – ground floor and two floors with apartments on each storey. Exterior walls are made of innovative prefabricated “ECO sandwich” façade panels which are constructed of recycled materials and have heat transmittance coefficient Uw= 0,2 W/(m2K). Prefabricated four-layer “ECO SANDWICH” facade panels have a total thickness of 42 cm and consist of an inner load-bearing layer 12 cm thick made of concrete with a minimum of 30 % recycled concrete aggregate, 20 cm thick rock wool thermal insulation layer, ventilated air layer and 6 cm reinforced concrete cladding. The building is designed in such a way to allow maximum use of solar energy in a passive way which allows the orientation of the building to the south. The sunny facades are maximally open, and the north is maximally closed. External windows are made from aluminium profiles with a triple low-e coated glazing. Heating system is forced warm-air heating combined with the mechanical ventilation with heat recovery. Condensing gas boiler is used as a heat source for a warm-air heating and partial floor heating in bathrooms. Roof solar collectors are foreseen for preparation of hot domestic water. LED lights are used as a general lighting source for apartments and common spaces.

Building owner

Private - apartments

Building type
Project type
Year of construction / major renovation

Construction: 2016
Major renovation: N/A

Total floor area
400 m²
Construction U-value
nZEB Parameters

Primary energy consumption: less than 45 kWh/(m2a)
Energy needed for heating: less than 15 kWh/(m2a)
Building tightness n/a
CO2 emissions n/a
Renewable share of energy 20 % (solar thermal energy)

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