Sustainable in every sense: Telli renovation in Aarau

Sustainability played a key role from the outset in the renovation of the Telli development in Aarau. Alongside energy efficiency goals, social factors were also important.

We have all heard the saying that every problem is also an opportunity. Sometimes it rings true, other times not so much. In this story about real estate emissions, the former certainly applies. The problem is a familiar one: buildings account for a large share of greenhouse gas emissions around the world – Switzerland included.

The opportunity concerns reducing or even eliminating these emissions and thus making a substantial contribution to creating a carbon-neutral society. AXA owns a great deal of real estate, so it has a special responsibility in this respect. A good example of how it is addressing this and why sustainability means more than just reducing the amount of CO2 you emit is the renovation of the Telli housing development in Aarau, one of the largest investments in AXA's real estate portfolio with some 581 apartments in blocks B and C.

Sustainability is about more than just reducing CO2 emissions

Ground was broken on the Telli development in 1971. The four huge apartment blocks were designed by the architect Hans Marti and are listed as significant to the region's cultural heritage. Situated in an expansive park that serves as an important leisure space for the whole of the surrounding area, they currently house an eighth of the city's population. It would therefore not be socially acceptable to force all the affected tenants to move out during the renovation. This is one of the reasons why the decision was made to renovate with tenants still in place, making this one of the largest construction projects of its kind in Switzerland. 

It should thus be clear that this renovation project is both necessary and challenging in terms of size and complexity. Inevitably, given its age, the development no longer meets the latest standards, especially when it comes to energy efficiency, but its cultural significance demands a cautious approach. Its sheer size makes involving the community and securing political support essential. With this in mind, the project stands as a shining example of sustainability in the broader sense being applied in practice, with social aspects taken into consideration in addition to energy efficiency and biodiversity targets, and transparent communication with all stakeholders absolutely essential.

A comprehensive, carefully thought-out renovation project

In keeping with the situation and requirements, an extensive renovation project was mapped out that aims to upgrade the Telli in various respects without detracting from its unique character. From an ecological point of view, two sub-projects are key. The first is a complete overhaul of the site's energy use that involves insulating the façade and installing a new district heating system as well as state-of-the-art ventilation. This will reduce CO2 emissions by around 1,000 tons a year. The second sub-project entails a partial remodeling of the park with more natural landscaping to provide a habitat for a variety of flora and fauna and a space where everyone living in the Telli can come together. The landscape architect's plans incorporate suggestions from the general public.

In the interests of social sustainability, shared spaces and more inviting outdoor areas are being created, for instance thanks to new lighting concepts and a community center. Of course, keeping rents affordable is also very important in this regard. 

The central challenge of our time lies in blazing a trail toward a carbon-neutral future for our global society while also safeguarding biodiversity. We can only do this if we enjoy broad acceptance and support locally. The renovation of the Telli development is an example of how all aspects of sustainability, both environmental and social, can be addressed.