Doubling Circularity in Homes Without Increasing Life Cycle Costs

Why It Matters

This research challenges the perception that circularity is inherently more expensive. It provides a practical roadmap for designers and developers to integrate sustainability into building projects, demonstrating that initial investments in recycled materials and modular design can lead to long-term cost parity and environmental benefits.

Key Finding

Design modifications to increase a house's circularity, like using recycled materials and designing for easier deconstruction, can be implemented without raising overall costs, up to a certain point.

Key Findings

• It is possible to double the LoC of a one-family house (from 0.20 to 0.41) without increasing its LCC.
• Achieving this increased circularity primarily involves substituting virgin materials with recycled or biological alternatives and using easily disassembled building products.
• Further increases in circularity beyond LoC 0.41 lead to a sharp rise in product costs and thus LCC, making it less economically viable.

Research Evidence

Aim: To investigate the relationship between the level of circularity and the life cycle costs of a one-family house.

Method: Design-oriented research

Procedure: The design of a one-family house was iteratively modified to increase its Level of Circularity (LoC). Life Cycle Costs (LCC) were calculated for each design iteration.

Context: Residential construction

Design Principle

Prioritize cost-effective circularity strategies by focusing on material substitution and design for disassembly.

How to Apply

When designing new homes or renovating existing ones, evaluate opportunities to incorporate recycled or bio-based materials and design building components for easy separation and reuse at the end of their service life.

Limitations

The study focuses on a single-family house; findings may vary for different building types. The economic viability of higher circularity levels beyond a certain point was not explored in depth.

Student Guide (IB Design Technology)

Simple Explanation: You can make houses more environmentally friendly by using recycled stuff and making them easy to take apart, and it won't cost more over the whole time the house is used.

Why This Matters: This research is important for design projects focused on sustainability, showing that environmental goals can align with economic feasibility.

Critical Thinking: At what point does the pursuit of circularity become economically prohibitive, and what factors influence this threshold?

IA-Ready Paragraph: This research indicates that increasing the circularity of residential buildings through material substitution (e.g., recycled or biological materials) and designing for disassembly can be achieved without increasing life cycle costs, up to a LoC of approximately 0.41. This suggests that designers can prioritize these strategies to meet sustainability goals while remaining economically competitive.

Project Tips

• When selecting materials, research the availability and cost of recycled or bio-based alternatives.
• Consider modular construction techniques or standardized connection methods to facilitate disassembly.

How to Use in IA

• Reference this study when discussing the economic viability of sustainable design choices in your design project.

Examiner Tips

• Demonstrate an understanding of how design choices impact both environmental metrics (like circularity) and economic factors (like life cycle costs).

Independent Variable: Level of Circularity (LoC)

Dependent Variable: Life Cycle Costs (LCC)

Controlled Variables: Type of building (one-family house), design and construction process.

Strengths

• Directly links circularity metrics to economic outcomes.
• Provides actionable design strategies.

Critical Questions

• How do fluctuating material prices affect the economic viability of circular design?
• What are the long-term benefits of higher circularity beyond direct cost savings (e.g., resource security, reduced waste disposal fees)?

Extended Essay Application

• An Extended Essay could explore the scalability of these findings to larger construction projects or different building typologies, investigating the economic trade-offs at higher levels of circularity.

Source

Exploring the relationship between the level of circularity and the life cycle costs of a one-family house · Resources Conservation and Recycling · 2020 · 10.1016/j.resconrec.2020.105149