Aroundtown has recorded another milestone in the ecological upgrading of its existing portfolio: the Delta Haus office building at Gustav-Stresemann-Ring 1 in Wiesbaden has been awarded the BREEAM "Excellent" rating. In its initial certification in 2023, the property had been rated "Good". The current result marks an increase from 41.89 per cent to 72.81 per cent. Nationwide, according to surveys as of October 2026, only around eight per cent of all BREEAM-certified properties hold an "Excellent" rating.
Efficiency gains in ongoing building operations
Technical adjustments in ongoing operations contributed to the improved rating. Heating is provided via district heating, resulting in zero on-site emissions from heat generation. Lighting systems across the outdoor and car park areas were fully upgraded to LED. A new building management system further optimises technical plant. Water consumption is centrally monitored via the digital Smartvatten system to immediately locate pipeline leaks. In addition, leak detection has been installed on air conditioning units to provide early warning of refrigerant leaks with high global warming potential.
Alongside energy performance factors, amenity qualities were incorporated into the audit. Featuring a triangular main volume, a glazed facade and a front-facing rotunda, the office building offers bright lettable spaces with expansive sightlines. In the categories of daylight availability and views, the property achieved the maximum score. For employees, 36 bicycle parking spaces were provided. Furthermore, an increased proportion of green space on the grounds supports local biodiversity.
Transport connections and portfolio context
Delta Haus is situated close to Wiesbaden central station and offers direct connections to the city centre and the Autobahn 66. Hessian state ministries, courts and public authorities are located a short distance away. Amenities in the building include fibre-optic connections, passenger lifts, and car parking spaces in the underground car park and outdoor areas. Mehl Gebäude Management assisted during the audit process. Alexander Rüb, Head of the National System Representation BREEAM D-A-CH at TÜV SÜD, explained that the improvement of around 31 percentage points demonstrated how much can be accomplished with existing properties through consistent effort. Benjamin Betzl Lopez, BREEAM Expert at Aroundtown, emphasised that numerous individual measures worked together at Delta Haus and encouraged the group to continue progressively expanding the sustainability performance of its existing portfolio.
Since 1990, the BREEAM methodology has assessed properties based on criteria such as energy, health, transport, materials and ecology. At Aroundtown, more than 70 per cent of commercial properties are now BREEAM-certified. Recent ratings include the Frankfurt Astropark with the highest level, "Outstanding", as well as properties rated "Excellent" in Berlin at Markgrafenstrasse 17-18, the Trevista in Eschborn, and a building at Gehespitz 50 in Neu-Isenburg.
