In many development projects, a product's sustainability performance is determined in the early stages of development. This is precisely where the necessary transparency is often lacking: Which material and joining technologies result in lower CO₂ equivalents (CO₂e)? How can the degree of circularity be increased without compromising functional, mechanical, or economic requirements? A key aspect of the it's OWL project " Sustainable Lifecycle Engineering " was therefore to make the relevant levers visible and understandable early on for Miele – with clear guidelines that can be integrated into everyday development and enable reliable decisions throughout the entire product lifecycle.

This impetus is crucial for the Sustainable Lifecycle Engineering (SLE) project: moving away from gut feeling and towards consolidated knowledge about the impact of design and construction decisions – especially regarding materials and joining techniques as key to repairability and recycling.

Five areas of action for sustainable product development

Miele's existing design guidelines and life cycle assessments (LCAs) were compared with jointly developed SLE solution approaches and consolidated on the basis of a compact and application-oriented recommendation for sustainable product development.

Five areas of action were derived that reflect Miele's sustainability strategy: user-oriented sustainability, durability, repairability, energy and efficiency optimization, and sustainable material selection.

"It was important to us that we didn't make decisions for others, but rather enabled them. With clear transparency regarding CO₂e and circularity right from the concept phase."

Max Wagner, Director Sustainability Miele

The goal is to enable developers to assess early on which choice – for example, recycled material versus virgin material – is the best from a sustainability perspective. And to simultaneously consider the physical, mechanical, and economic requirements. The recommendation is intended as a "soft" guideline: it provides context and orientation without predetermining decisions.

“It was important to us that we didn’t make decisions for people, but rather enabled them. With clear transparency regarding CO₂e and circularity right from the concept phase,” says Max Wagner, Director Sustainability Miele.

Targeted identification of high-impact components

Within the action area of ​​"sustainable material selection," existing and emerging products are examined with regard to CO₂e emissions and circularity levels. Particular attention is paid to high-impact components (in terms of their influence on CO₂e emissions and circularity levels, not in terms of impact resistance): assemblies whose material and design choices have a particularly strong influence on the environmental footprint and circularity.

Using a proprietary development, these high-impact components can not only be automatically identified, but their CO2e reduction potential can also be specifically determined. This is done by specifying defined properties, such as modulus of elasticity, tensile strength, or density, based on a constant construction volume.

Image: Potential for CO₂e reduction of selected materials compared to the starting material ABS-GF20, taking into account defined input parameters and at constant volume (e.g., E-modulus > 1 GPa, tensile strength > 20 MPa, density > 0.8 g/cm³).

Results and benefits

The interplay of SLE expertise, Miele guidelines, and LCA data has resulted in a tangible development recommendation that combines sustainability and engineering practicality. It accelerates the assessment of key issues – such as comparing recycled and virgin materials. At the same time, it highlights typical trade-offs: mechanical properties, processability, costs, and quality variations.

"Transparency regarding CO₂e and circularity across the entire life cycle, even at the component and part level, is extremely helpful in identifying high-impact levers."

Christian Neese, Project Manager Miele

One concrete result is simplified material diagrams, for example for plastics, which systematize the selection process. They visualize where recycled materials save CO₂e compared to virgin materials and how circularity levels change – including information on joining technologies that support disassembly, repairability, and recycling.

“Transparency regarding CO₂e and circularity across the entire life cycle, even at the component and part level, helps enormously in identifying high-impact levers,” says Christian Neese, project manager at Miele.

Design for circularity in practice

The Miele design study VOOPER , a circular vacuum cleaner, illustrates what "Design for Circularity" can look like in practice: connection concepts, modular construction, and material choices work together to enable circularity and durability. The VOOPER was presented at IFA 2024. The study not only highlights the potential savings through circular design but also contributed internally to reducing plastic materials to 15 percent of the previous amount.

Transition to processes and scaling

The next step is scaling into practice: The recommendations and material overviews will be integrated into standard workflows, early-stage reviews, and training formats. In parallel, the database will be expanded – CO₂e, circularity, dismantling rates, recycled content, typical quality variations, and cost paths – to further refine the comparisons.

Pilot projects in different product groups deepen the knowledge, for example regarding ease of disassembly vs. service life or recycled content vs. mechanical performance.

Guidelines for circular product design

In line with the principles of Design for Circularity, specific guidelines are defined: preferred connection technologies (e.g., screw/plug connections instead of adhesive bonds), modular architectures, defined dismantling paths, and spare parts strategies that increase repairability. These are accompanied by key performance indicators (KPIs) for measuring impact – CO₂e reduction per device, circularity levels, repair rates, material return rates – and regular monitoring.

With this new recommendation, Miele lays the foundation for decisive sustainability in product development: transparent enough to act quickly, and at the same time flexible enough to balance technology, costs and performance in the project context.

The VOOPER makes the approach visible, the simplified material diagrams make it applicable – and the upcoming pilot projects will further refine it. In this way, a development routine is gradually emerging in which sustainability is not an add-on, but an integral part of good engineering.



The article " Transparency as a lever: For Miele, sustainability is an integral part of good engineering" first appeared on it's OWL .