Sustainable Architecture

The building sector is responsible for 40% of Switzerland's CO₂ emissions. Half of this is emitted during construction, mainly in the production of steel, cement, glass and plaster. While saving energy during operation has long been an issue, society is only slowly becoming aware of the "grey energy" behind it.

Our mission is to avoid unnecessary CO₂ emissions. A new replacement building needs to be scrutinised. In terms of emissions, it is usually only worthwhile if it blocks greater densification, if significantly more people can share the same plot of land after demolition.

We extend the life cycle of existing buildings by upgrading them and adapting them intelligently to changing requirements, but we also scrutinise these.

Buildings from the inter-war and early post-war periods often have sensitive envelopes. Building owners are often faced with a trade-off between aesthetics and the environment. And a lack of satisfaction with the design result can seriously dampen the joy of investing in climate-friendly measures.

Fortunately, legislation is also slowly moving away from the primacy of energy efficiency in favour of the goal of reducing CO₂ emissions. The old and new targets are still linked, but today it is no longer the thickness of the insulation that counts, but the CO₂ balance of the primary energy used to meet the energy demand.

In our view, this creates a long overdue window of opportunity for existing buildings, as strategies to reduce their CO₂ emissions have been available for some time. Effectively reducing CO₂ emissions in the following order

Focus on fossil-free energy sources
Increase your own power supply and (only) then
Insulate the envelope

As an alternative to SIA 380/1 certification, most cantons also recognise Minergie^® certification. The Minergie^® Association offers four different system renewal certifications for existing buildings.

These are particularly interesting in the canton of Aargau: with the rejection of the new Energy Act 2020, the introduction of national weighting factors for energy sources also fell victim. These are used to weight energy sources for system verification according to their contribution to the CO₂ balance: The energy consumption of a pellet heating system is halved compared to a fossil heating system, while that of a PVA is even set to zero. In the case of Minergie^® certification, the credit is nevertheless recognised. In certain situations, a Minergie^® certificate may also allow a more sensible approach in the canton of Zurich.

The Cantonal Energy Performance Certificate (GEAK^®) is the first step towards energy-efficient renovation. It is the official cantonal energy label and is financially supported by most cantons.

A GEAK^® indicates the energy class of the building envelope and building services of an existing building in seven classes. It roughly indicates the need for action and contains recommendations for energy-related measures. A GEAK^® report is free of charge for the owner.

In addition to the building envelope, the GEAK^® Plus also shows the overall energy efficiency. It is slightly more comprehensive and shows two to three options for energy efficiency improvements tailored to the specific building.