AREA: 5,062 m2
PHASE: before renovation


Construction description

Office building is a concrete structure building with 6 over ground floors and underground floors with garages.

Uses distribution

Ground Floor: Reception lobby, offices, small shop.

Upper floors: offices

Basement: parking, technical systems room.

Envelope characteristics

Supporting structure and external walls are from reinforced concrete with thermal insulation from mineral wool. Plastic windows are with thermally broken frames and double glazing.  The roof is insulated above the reinforced concrete slabs, partly a slope roof from lightweight system.

Building Systems

  • Heating and DHW: low temperature gas boilers
  • Air Conditioning: air-cooled chiller, FCU
  • HVAC controls: central for heating. Thermostats for FCU units.
  • Lighting: Lighting partly renovation took place already. Fluorescent lamps are partly replaced by LED retrofits, Digital Addressable Lighting Interface is installed.


The energy related renovation measures proposed by ALDREN aim to improve the Energy Efficiency of building until the level of ALDREN NZEB. Measures consist in additional insulation of some parts of envelope and ceilings, replacement of windows double glazing by triple glazing and the change of systems for heating and cooling and hot water preparation. Improvement of lighting systems is also part of proposed measures. Besides the new lighting system using LED luminaires a control system the control options for lighting are proposed to be applied that use the dimming for constant illumination (illuminance sensor), dimming or switching depending on the intensity of daylight (brightness sensor), switching depending on room occupancy (PIR motion sensor) with use of already installed Digital Addressable Lighting Interface (DALI).

The renewable energy generation through Photovoltaic Panels is proposed also based on a high interest by owner even if the roof available with appropriate orientation is limited.

Proposed measures are reported in the Renovation Roadmap and summarised in European Voluntary Certificate.  They are evaluated also from the point of view of investment value and improvement of indoor environment.



Non-renewable Primary Energy savings: 71%

Energy use savings:

Heating: 92%

Cooling: 73%

Ventilation: 50%

Domestic hot water: 58%

Lighting: 46%

PV Production: 6.7 kWh/(m2.a) from which 5 kWh/(m2.a) are self-used in building and 1.7 kWh/(m2.a) are exported.


This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 754159. The information in this publication does not necessarily represent the view of the European Commission.
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Any duplication or use of objects such as diagrams in other electronic or printed publications is not permitted without the author’s agreement.


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