With increasing policies and societal pressure, the environmental impact of product design has become a widespread concern. Life Cycle Assessment (LCA) is a key method used to quantify the environmental impacts associated with the manufacture, transport, use and disposal of a product. While LCA provides valuable insights, it is primarily used as a retrospective evaluation tool rather than to inform design decisions. This is largely due to the complexity, data-intensive nature and misalignment of existing LCA software with the design workflow. As a result, designers struggle to incorporate LCA insights into their decision-making process.

To bridge this gap and lower the threshold for LCA adoption, Polaris Sustainability, a start-up company aiming to specialise in LCA software, initiated this thesis project to explore the development of a designer-friendly LCA tool. The aim is to make LCA more accessible by integrating it seamlessly into the design process, allowing designers to apply LCA in an ex-ante manner, assessing environmental impacts before their products are finalised. This approach helps designers integrate sustainability considerations early in development when changes are still flexible. By addressing environmental impacts before decisions become too costly or difficult to reverse, it enables more sustainable design choices.

The research identified two key challenges: the complexity of LCA software and the lack of alignment with design workflows. Designers often struggle with critical LCA steps, such as defining Functional Units (FUs), handling incomplete datasets, and interpreting results. At the same time, different design stages require different levels of environmental insights. Recognizing LCA’s value at each stage (e.g., ideation or embodiment) can improve its integration into decision-making. Designers also need structured support in performing LCA, including guidance on working with incomplete data, using proxies, and simplifying LCA terminology to make it more intuitive and actionable.

To address these issues, a digital prototype was developed through UX design methods and usability testing, featuring a wizard-based approach that guides designers step by step through the LCA process. Key features include accessible databases for material and process data, uncertainty management for handling incomplete datasets, and clear data visualizations to help designers understand and compare environmental impacts.

A feasibility discussion with software developers confirmed that the tool’s core functionalities, such as guided workflows and real-time impact assessments, are technically feasible. However, some features will require excessive computing power, making them prone to error. Future development should focus on creating a functional prototype, gathering additional user feedback, and enhancing automation to reduce cognitive load. Developing databases tailored to designers' material and process knowledge will be essential to improving usability.

By refining the user experience, addressing data challenges, and modelling the back-end, Polaris will be able to develop a practical LCA tool that supports environmetnal design decisions. Collaboration with academia and industry, along with pilot studies, will further strengthen the tool, ensuring it is both methodologically sound and aligned with practical design needs before its full launch.

This thesis addresses the urgent need for more effective environmental sustainability assessments that can be integrated into the early stages of product design. Designers play a critical role in the environmental impact of their products, yet they often struggle to integrate environmental assessments into the early stages of design. Traditional linear production models cause environmental challenges such as resource depletion and pollution, while the Circular Economy offers a more sustainable alternative by aiming to reduce waste and close resource loops. However, simply applying CE principles does not guarantee sustainability, as unintended effects such as "CE rebound" can occur. This highlights the need for advanced tools that can accurately assess the environmental impact of circular designs early in the design process.

The primary objective of this study was to establish the requirements for an early-stage quantitative assessment tool that integrates Life Cycle Assessment (LCA) into circular design processes. The research aimed to determine how LCA can be effectively incorporated into early decision-making stages, identify suitable methods for evaluating circular design strategies, assess the usability of existing LCA tools, and address the challenges designers encounter when implementing environmental sustainability assessments.
The research was conducted in three phases. The first phase involved a detailed examination of designers' decision-making workflows. In the second phase, existing sustainability assessment methods and LCA tools were evaluated. The third phase focused on developing a program of requirements for a new assessment tool. Methodologies included comprehensive literature reviews, analysis of grey literature, interviews with experts in environmentally sustainable design, and usability testing of existing tools.

Key findings revealed a mismatch between the complexity of current LCA tools and the practical needs of designers in the early stages of design. Most tools are either too complex or too simple, making them unsuitable for the iterative and creative nature of early design processes. Designers often rely on intuitive approaches that are not adequately supported by traditional, data-intensive LCA tools. To address this gap, the study proposed a dual-interface tool: one interface for designers to facilitate easy integration into creative workflows, and another for sustainability experts to manage detailed modeling and scenario analysis. The tool emphasizes ex-ante LCA for predictive analysis, allowing for early-stage assessment and scenario modeling using estimated data. Additionally, integrating qualitative assessments alongside quantitative data will provide a more comprehensive evaluation of circular design strategies. This holistic approach aims to align LCA tools with designers' practical needs, enhancing the integration of environmental sustainability into early-stage product design.

The research concludes with recommendations for developing user-friendly LCA tools, improving the assessment of circular design strategies, and fostering collaboration between academia, industry, and tool developers. These advancements aim to improve the integration of environmental sustainability into early-stage product design.