The building consists of four residential storeys which have been renovated to improve energy efficiency and have achieved a pre-certification of the step-by-step EnerPHit standard. During the renovation the building was insulated to the passive house standard of a new building and windows have been replaced with triple glazing. Moreover, a ventilation system with heat recovery has been installed.

Thermal envelope

Exterior wall: 25mm interior plaster
250mm concrete
50mm mineral wool
120mm vertically perforated brick
200mm EPS-F PLUS
7mm exterior plaster
U-value = 0.12 W/(m²K) 

Basement floor/floor slab: 10mm tiles
50mm screed concrete
40mm fill
200mm reinforced concrete
100mm EPS-F Plus
5mm interior plaster
U-value = 0.27 W/(m²K) 

Roof: 10mm plaster
120mm reinforced concrete
30-150mm gradient insulation board EPS-W20
10mm black insulation 2 layer.
180mm ROOFMATE SL-AP
2mm fleece
50mm gravel
U-value = 0.14 W/(m²K) 

Mechanical systems

Ventilation: Centralised ventilation system

Heating installation: Electrical devices with intelligente controls have been installed.

Domestic hot water: Decentralised, electric hot water storage

Ecological aspects: 49.4 kWp PV modules on the flat roof

PHPP values

Air tightness: n₅₀ = 0.59/h 
only one staircase tested

Annual heating demand: 28 kWh /(m²a ) calculated according to PHPP

PER demand (renewable Primary Energy): 95 kWh /(m²a ) on heating installation, domestic hot water, household electricity and auxiliary electricity calculated according to PHPP  

Generation of renewable energy: 51 kWh /(m²a ) based on the projected area