As a project targeting Passivhaus certification, ECHO.1 is optimised to perform, delivering thermal comfort, uncompromised acoustics, and superior air quality with minimal energy requirements.

Designed for net-zero energy outcomes and with sustainable building materials, ECHO.1 is about making responsible choices that will reverberate for generations.

Architecture & Design: Can you describe the initial vision for this project and how it evolved over time?

C. Street Projects: At C. Street we want to deliver real value for our clients, understanding that purchasing a home is a big decision, and that the impact of our decisions in design and construction will last for decades. We really focused on improving quality of life, and the living experience.

The Passivhaus standard, with its clear, scientific framework, presented a compelling model that we have studied for some time. ECHO.1 presented an opportunity to pioneer the Passivhaus standard commercially and put our approach into practice. The site’s location in Hawthorn, with favourable access, orientation and zoning, allowed us the freedom to optimise the building’s performance characteristics.

What were the biggest challenges you faced during the design and construction phases, and how did you overcome them?

The technical aspects of Passivhaus make it challenging to deliver consistently at scale. Achieving the verified airtightness of 0.6 air changed per hour (ach) is a significant risk, where failure of this test at the end of the project will jeopardise certification. Managing thermal bridges between the different material interfaces and junctions was also difficult.

Achieving certification requires documenting detailed evidence of installation and passing key commissioning tests. Administering this unfamiliar process with the trades and head builder required extensive supervision and training by C. Street.

Our approach was to ensure the building form was compact and efficient, and to implement a continuous insulation system using Durra Panel straw board, mineral wool batts and XPS insulation around the entire perimeter of the building, with an airtightness membrane.

Details were standardised across the eight townhouses as much as possible, and scale prototypes were constructed to explain the sequence and methods. C. Street worked closely with suppliers, trades and our Passivhaus consultant to achieve certification in the end.

How did you ensure that the project met the client’s needs and expectations?

The energy model that Passivhaus uses is very detailed and has been shown to closely match actual performance across different climates. Once the design is found to deliver passing results in the model, it is a matter of executing the details accurately on site.

The hallmarks of a Passivhaus building - stable internal temperatures between 20-25°C, quietness, excellent indoor air quality, and low operating expenses – are guaranteed for every ECHO.1 resident because of the quality assurance framework embedded in the certification process. This directly improves our clients’ quality of life, and speaks to the value we are delivering.

Were there any unique or innovative techniques or materials used in this project?

ECHO.1 implements several new materials in townhouse construction, not seen before in Australia. Durra Panel, which is a 50mm compressed straw board from Bendigo, was used as continuous external insulation to mitigate thermal bridging through the timber frame.

Proctor Wraptite was used as a vapour permeable, airtight barrier. Similar liquid applied membranes that are also vapour permeable were applied to block and concrete surfaces for airtightness. Triple glazed windows, doors and skylights from Europe have been installed, providing excellent thermal performance.

Each home is also ventilated with a Zehnder Heat Recovery Ventilator, providing the benefit of continuous filtered fresh air without having to open windows. ECHO.1 is also future proofed with each townhouse having a dedicated 4.4kW PV system, 10kWh battery and Type 2 EV charging.

How does this project fit into your broader portfolio and design philosophy?

Our design philosophy is to focus on what matters most – being comfortable, happy and healthy in your home. To achieve this properly, fundamental building science principles need to be applied correctly to the design, and we cannot rely on guesswork.

C. Street aims to shift the narrative for buyers in the marketplace, providing homes that can be trusted and relied on in the face of a changing climate and rising energy costs. We are confident that these aspects will be valued in time, and will continue to offer homes built to the world’s best performance standard.

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