Located on a quiet suburban street in Melbourne, Australia, Life Cycle is a thoughtful extension to an existing weatherboard house that integrates sustainability with a family-focused design. The project by Steffen Welsch Architects is conceived to enhance the existing home’s functionality while strengthening its connection to the surrounding community. By prioritizing passive solar strategies and sustainable design principles, the project is designed to minimize both embodied and operational carbon footprints.
The layout is structured to create clearly identifiable zones within the home. The original section now serves as a home office, parents' quarters, and other essential spaces, while the newly added rear extension is dedicated to communal living areas on the ground floor and children’s spaces on the upper level. The transition between old and new includes a flexible zone with a spillover lounge, a winter garden that acts as a thermal buffer, and a cozy lobby overlooking a small fishpond. This adaptable setup is designed to evolve with the family's changing needs, allowing for the seamless reconfiguration of spaces.
Passive design strategies
Sustainability is embedded throughout the project, with passive solar design playing a central role. To keep the house cool in the summer, a strategically placed pond southwest of the lounge draws in cooler air. The winter garden extends the lounge area, serving as an additional layer of insulation. Above the dining space, a netted void functions as a thermal chimney, helping to preheat the upper floor during winter and expel hot air in the summer.
The design also incorporates internal windows to enhance natural light while facilitating cross-ventilation, reducing reliance on artificial climate control. An external timber frame provides much-needed shading, while filtering light to reduce glare. Additionally, elevated planters near windows not only support small herb gardens but also mitigate radiant heat, further improving indoor comfort.
Energy-efficient technologies
A 7.6kW solar photovoltaic system powers the home, contributing to its strong score of 6.3 on the Australian rating system NatHERS. Water efficiency is achieved through fixtures that conserve water and a 4,000-liter rainwater tank that supplies toilets and irrigates the garden. In-screed hydronic heating, powered by electricity instead of gas, reduces the home’s carbon footprint. Timber, known for its low embodied carbon and ability to sequester carbon over time, is used extensively throughout the project, including in recycled flooring.
Mechanical systems are optimized to further reduce the environmental impact. The air conditioning system uses Daikin’s R32 refrigerant, which has a significantly lower Global Warming Potential (GWP) than traditional options. For hot water, the system uses CO₂ as a refrigerant, with a GWP of just 1, a far more sustainable choice compared to conventional alternatives like R32 and R410a.
Community connections
Beyond its environmental considerations, the project strengthens the home’s connection to the neighborhood. The front of the property was opened up, and the verandah was extended to foster engagement with the street. The design respects the traditional architectural forms of the area while introducing modern elements like articulated timber structures that smoothly transition into the landscaped garden. Elevated planters and a rooftop garden enhance local biodiversity, while the upper floors offer curated views of nearby trees and rooftops, reinforcing the connection to the natural surroundings.
Carbon and life cycle assessments
Steffen Welsch Architects has undertaken several measures to better understand and quantify the environmental impact of its projects, performing carbon and life cycle assessments. The main objectives of this initiative, according to the studio, are first, to establish a baseline level of emissions, which will serve as a benchmark for evaluating future designs, and second, to assess how the firm’s projects perform relative to the average Australian residential building, providing a clear point of comparison.
According to an analysis made using RapidLCA, an intuitive application designed to streamline life cycle assessments for sustainable housing, enabling users to measure, improve, and report environmental impacts efficiently, Life Cycle made an 79% improvement against Australian benchmarks. It did so through intelligent design, and the incorporation of the following building products:
In-screed heating by Mercury heating and cooling
Recycled blackbutt timber by Urban Salvage
Plywood panels and cabinetry by Timberwood Panels
Double glazed timber windows and doors by Binq Windows
