The "Heidelberg Student Living" project showcases the energy efficiency and economic performance of an innovative form of the modular system for buildings with a timber structure, developed by LiWooD AG in Munich. The combination of an energy-efficient building envelope, air/water heat pumps and a high-performance PV installation reduces the costs for heating and hot water to practically nothing. The Schüco Alu Inside system windows, which are energy-saving windows to passive house standard with triple glazing and integrated window rebate ventilation, play a key role in the concept and design of the building envelope.

As part of an EU-wide specification for tender, the client – Studentenwerk Heidelberg student services – set the brief for the student housing, which was to create high quality apartments for the maximum number of students using the smallest amount of space possible. Munich-based LiWooD AG impressed in the competition with their innovative modular system, which not only has an outstanding energy efficiency profile but can also guarantee fast construction due to its on-site installation and completion. After the foundations were laid, it took only five months to finish the three building structures. This is due not least to the fact that the development, planning and building work for the "turnkey construction" were all logistically optimised with everything coordinated by a single source. The most remarkable feature of the construction process is that the modules were assembled in a "field factory" directly on site, regardless of the weather. On average, six modules can be completed there and attached to the buildings in storeys each day.

The student apartment blocks consist of three five-storey buildings with 265 bedrooms in attractive one-bedroom to three-bedroom apartments and 12 reading, studying and service rooms. Aside from their compact design, a high-quality living environment is achieved by aligning the apartments systematically to the east, south and west. This is expressed in the buildings 660 (yellow) and 661 (blue) by means of a single-row construction orientated east/west with south-facing apartments. Within its disparate landscape, the three new building structures form an homogeneous demarcation line with neighbouring Klausenpfad to the north.

With the graduated grey shades of the outer façade, the colour concept developed by LiWooD highlights the commonality between the three building structures. At the same time, by allocating the different primary colours yellow, blue and red to the buildings at structure level, an individual identity is created for each. The theme of the irregularly aligned slabs in three graduated shades of grey is repeated in the interior corridors which are also clad with coloured fibre cement panels, creating the impression of spatial depth inside the narrow, functional corridors.

The concept of the student halls of residence stands out not only due to the consistent use of sustainable building materials, but also thanks to its ambitious aim of reducing the energy used for heating and hot water to almost zero. In practice, this has been a complete success due to the combination of an energy-efficient building envelope, air/water heat pumps and a high-performance PV system, the solar output of which meets the energy requirements of the entire building on a yearly basis (see energy efficiency profile).

The patented Schüco Alu Inside energy-saving windows contribute significantly to reducing energy loss through the building envelope. These are PVC-U profile constructions to passive house standard which do not contain the standard steel reinforcement. These innovative window systems can be manufactured economically using patented aluminium profile rolling technology on an industrial scale. A considerable weight saving combined with very good structural values qualify this product series in particular for use as window and door units in the construction of passive houses, as these highly insulated window units have significantly heavier vent weights due to their triple insulating glass composition.

This was also the case for the system window units in the Heidelberg student halls of residence, where the coated triple glazing (Ug = 0.5 W/m²K) in conjunction with the high insulation 7-chamber profile system from Schüco Alu Inside boast top-end thermal insulation properties of Uw = 0.74 W/m²K. An improved sound reduction value of 32 dB and optimised security due to the increased basic depth of the system are positive additional benefits of this new generation of windows.The high insulating effect of the windows required additional measures to be taken to achieve a comfortable room temperature. Even when closed, the air exchange is performed by an additional feature of the windows – the integrated Schüco window rebate ventilation. This allows air to be exchanged even when the windows are closed, using two small individual ventilators between the outer and vent frames. The ventilation vents are fitted with different counterweights that control the air exchange depending on the wind load. Air entry in the upper window area and volume flow restriction ensure perfectly smooth air convection in the room.