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Engineering and architecture firm GREISCH chose SageGlass dynamic glazing to renovate the glass roof of its offices in Liège, Belgium

A smart solution that guarantees optimal comfort and preserves the existing structure


Interior of a stunning glass atrium with tinted glass walls and ceiling

GREISCH, one of Europe’s leading engineering and architectural firms, undertook expansion works in 2008 at its offices in Liège, Belgium. This work involved building a sleek atrium and walkways to seamlessly join the old and new buildings. The ventilation/air conditioning system was adapted in line with the new configuration. However, over the years, increasingly frequent heat waves have affected the comfort of some employees. In 2020, GREISCH conducted a satisfaction survey among its employees. Its objective was to clearly identify the problems faced and to quickly find solutions so that the teams could work in a comfortable environment in both summer and winter. The results were decisive. The fully glazed atrium (242 m²) had to be equipped with shade systems in order to control:

  • heat input
  • temperature differences between the different floors
  • glare on computer screens.

After researching the various systems on the market, the GREISCH team responsible for the project chose SageGlass* electrochromic glazing, which automatically and discreetly adapts its tint in response to the sun’s path. In addition to the required solar control, this smart glass helps maintain incoming natural light and a constant connection with the outside world. This means employees benefit from the thermal, visual and acoustic comfort that supports concentration. In terms of client benefit, GREISCH saves on its energy bills by limiting the need for air conditioning and eliminating maintenance costs related to conventional shade solutions such as blinds.

* Holder of the “Solar Impulse Efficient Solution” quality label.

Interior atrium of a glass office building and glass walkways

Photo credit SageGlass – photographer Marc Detiffe

The advantage of renovating

The 140 SageGlass panes (35″ x 90″ and 35″ x 51″) were installed in less than three months by Belgian company GROVEN+PORTAL and commissioned in the spring of 2021 by SageGlass. They were installed on the entire glass roof in place of the old ones and do not apply too much weight to the wood and steel structure. This means it doesn’t need to be reinforced, which is a real advantage in terms of cost and speed of installation. The glass roof’s sealing system was also completely redesigned, and the electrical power cables were concealed in the covers positioned on the outside of the glass.


A renewed sense of well-being at work

“We have planned with SageGlass to conduct a comprehensive comfort study next summer in order to obtain concrete figures. In just a few months, employees have been able to feel a noticeable difference, particularly between last July and September, and a few weeks ago in March with the first days of good weather. They’re really pleased and no longer have to deal with glare or temperature issues. They enjoy a comfortable and consistent temperature on all floors while reducing the use of air conditioning,” explains Christophe Dartois, Project Manager in Specialized Technology at GREISCH.

Photo credit SageGlass – photographer Marc Detiffe

Photo credit SageGlass – photographer Marc Detiffe

Simple installation and smart control managed by SageGlass

The dynamic glazing is delivered by SageGlass ready to be installed. It’s fitted just like conventional glazing and then an electrician takes care of the electrical connections. They are connected to two sensors on the roof, which follow the sun’s path through 360° in order to automatically and seamlessly regulate the tint of the glazing: from the “Clear” state with a solar factor of g = 0.38 and a light transmission of LT = 60% to the “Maximum” state with a solar factor of g = 0.05 and a light transmission of LT = 1%.

The settings were programmed by the SageGlass team. It set up various usage scenarios based on the specific needs of the GREISCH office. If necessary, they can be adjusted remotely by SageGlass technical assistance after several months of being in service. A “manual” mode is also available via the SageGlass wall-mounted touch screen or via a tablet linked to the Building Management System for ad hoc use. For example, this is useful if you need some shade to view a projection.


Photo credit SageGlass – photographer Marc Detiffe