The real estate industry is increasingly confronted with the effects of climate change, particularly extreme heat periods. Michael Farmakis, Managing Director of City 1 Group, notes that this will gain similar relevance to the heating law in the recent past. The company, operating in Germany and Greece, is developing construction concepts that keep interiors tempered even at high outside temperatures without continuous air conditioning. This is particularly relevant in view of Germany's new heat record, which was recorded on 27 June at 41.8 degrees Celsius.
Structural Measures in Neu-Isenburg and Athens
An example of this strategy is the 'Epsilon Office' building in Neu-Isenburg at Friedhofstraße 90. There, City 1 Group leases approximately 4,000 square metres of office space across nine units. Cooling is based on several coordinated structural elements. External Venetian blinds serve as primary sun protection and prevent direct solar energy from entering the building envelope. Full air conditioning with fresh air supply regulates air exchange. Furthermore, 3-metre-high ceilings help warm air circulate above users' head height. An underfloor cavity accommodates pipes for cooling and technical equipment. The building has a final energy requirement of 86 kilowatt-hours per square metre per year and is heated with wood pellets, corresponding to energy efficiency class B. Mr Farmakis highlights that the decision for these solutions was consciously made in 2019 to ensure a long-term amortisation over twenty years, even though the initial investment costs were higher.
The effectiveness of these measures is confirmed by tenants. Nikola Markovic, Managing Director of Celius Intensivpflege GmbH, which has occupied approximately 370 square metres of the building since April 2025, reports a positive impact on the working atmosphere and employees' concentration during the summer months. City 1 Group is pursuing a similar concept in the 'Icon Living' project on the Athens Riviera. The project, consisting of two five-storey buildings with a total of 15 apartments between 140 and 400 square metres, is located on an approximately 3,000 square metre plot in Glyfada. Although the apartments are west-facing and thus exposed to direct afternoon sun, architectural solutions have been implemented to prevent overheating while maintaining views of the golf course, sea, and sunset. Green roofs, water features between the buildings, and a 22-metre communal pool complement the outdoor facilities.
Natural Cooling Concepts and Future Developments
In Frankfurt's Holzhausenviertel, City 1 Group implemented another natural cooling strategy for the 'Edenholz' ensemble. Existing, mature trees were not felled but integrated into the planning of the four residential buildings. These trees provide shade on the spacious outdoor areas between the buildings. Michael Farmakis notes that while preserving trees requires additional coordination processes with authorities during the construction phase, it provides immediate shade, unlike newly planted trees, which only reach a comparable size after decades. The 'Edenholz' ensemble was awarded the iF Design Award in 2018.
For the coming years, City 1 Group plans the realisation of ten further real estate projects with a total area of 56,000 square metres of living space, equivalent to approximately 650 new apartments. Of these, around 200 units are scheduled for construction in Dreieich, Neu-Isenburg, Hochheim, Wiesbaden, and Frankfurt within the next twelve months. For each of these projects, it will be examined from the outset how the buildings can be kept cool without continuous air conditioning. Farmakis emphasises that the initially longer planning time for external Venetian blinds, the integration of old trees, or orientation according to the sun's position is an investment that pays off in the long term for residents and users.
