The Hütt 01 PassivHaus : Tomorrow's House Today

The architectural response beautifully integrates functional playfulness & attention to detail with highly sustainable construction techniques and materials. The resulting home showcases new technologies like Cross Laminated Timber (CLT) with low VOC finishes, natural wood-fiber insulation, thermal-bridge-free high-performance windows, heat-recovery ventilation, a super-airtight building envelope, green walls and planters for natural air purification, and aquaponics.

Through a professional design process Hutt 01 achieved “Passivhaus Premium” certification (the highest possible category) not only meeting but exceeding expectation. It utilizes high-efficiency appliances with heat pump technology, solar photovoltaic and battery, integrated active shading, and recycled and/or natural materials throughout. Product selections are based on sustainability, longevity and embodied energy, e.g. recycled bricks (carbon-zero), natural Woodfibre insulation and mass-timber structure (carbon-negative), recyclable timber floors with natural oil finishes and cradle to grave/cradle certification.

Showcasing prefabricated structural CLT panels with finished interior surfaces not only provides carbon footprint reduction, and time and cost savings, but also a reduction/removal of additional finishing trades and materials like plastering. Timber is featured in raw and finished forms, as well as natural stone and clay render. The design itself negotiates the narrow wedge-shaped site by drawing on familiar forms & a restrained palette of finishes. Skillfully articulating space and volume, forging a sense of generosity within its tight confines. The building plays with its triangular site geometry, generating soft lines & angles both in plan & section. A green roof and rain garden assist with stormwater retention as part of the WSUD (Water-Sensitive-Urban-Design) concept, utilizing over 90% of stormwater on site. The home is intended to be a testbed of new ideas and brave innovations, with data collected to demonstrate the utility and benefits of these cutting-edge approaches. It is an ongoing, organic work in progress.

The Hutt 01 Passivhaus reclaims a forgotten, unappealing piece of land in the middle of Melbourne’s urban jungle to provide a beautiful, functional, future proofed family home. An inspirational and thoughtful response to the challenges facing the built environment in a changing climate. Promoting urban densification to create more sustainable cities, a call to rethink how we approach residential building in Australia. The home has been designed to be flooded with natural northern light.

The 4 bedrooms, 2 living space, 3 bathroom and roof garden has a generous feel, despite its internal site footprint of only 78 sqm. The dynamics of the house play on the balance between inside & out, between nature & human made. A biophilic design approach ensures connection to nature is evident in every aspect of the building. Bespoke detailing, joinery insertions and playful details have been crafted carefully. From the freestanding custom vanity (designed in house) to concealed fittings and full-height panels that hide nooks, openings and cupboards. Cubby-holes between kids' rooms, hanging nets and a living green wall provide a contemporary living experience that combines playful adventure with luxury living and high levels of sustainability.

With this project, we challenged current Australian construction standards, and showcased what’s possible on a small urban block in terms of a sustainable development. The home has been built not just as a functional and welcoming family home, but also as a show home, to run tours and seminars, to demonstrate ideas around sustainable architecture. A prototype for many to follow. Engaging with the public is important to change perceptions of what a sustainable house can be, allowing people to personally experience what a well-balanced home built to Passivhaus standards feels like. Sustainable building needn’t sacrifice aesthetics nor lifestyle if done well, and it shouldn’t cost the earth.

The Hütt 01 utilizes novel, innovative materials and construction technologies to not only meet, but far exceed, the clients’ expectations. An outcome achieved through effective collaboration with consultants and trades to work through design details and bring it to fruition. This project is a welcoming, comfortable and fun family home, and an experimental research project, trialling - and showcasing with regular tours/events - new innovative ways of building a home.

Some of these examples include;

• Cross Laminated Timber (CLT). We identified a construction solution that would make Passivhaus simpler for local trades and builders, encouraging more to participate, learn and upskill in the Passivhaus process, particularly those new to the approach. CLT itself can provide for an airtight layer, making airtight detailing less complicated.
• Thermal-bridge-free windows. We have used different high-performance window types in this project, to research and monitor performance in the long term. By placing them fully outside the mass-timber structure and within the insulation layer, the resulting R value remains the same all around - thereby eliminating thermal bridges around the windows.
• Concrete. In keeping with the sustainability objectives of this project, the use of concrete in the building has been minimized, due to the high contribution of cement production to global CO2 emissions (8-13%). Concrete usage has been limited to in-ground structure, a concrete slab and a localized screed in the sunken lounge. The concrete used here has been developed with Boral specifically for this house, with 70% cement replacement, it has been used here for the first time ever.
• Integrated Shading. We have experimented with 7 different ways of integrated shading in this project. One is a traditional passive solar design deciduous plant shade and the remaining six are different types of vertical and horizontal active shades, some motorized and some manual, to assess effectiveness for future improvements.

Hütt 01 has been designed and constructed to be highly energy efficient, with the potential to use up to 90% less energy than current building stock, far exceeding the current national construction code energy requirements. This house incorporates a 11.5kW solar PV system (plus battery) neatly integrated into the design. Passivhaus planning procedures and calculations are undertaken during and post documentation, ensuring there is no gap between the expected and actual building performances. The outcome: peace of mind that a home will and is comfortable, healthy, quiet and affordable to run. We have learnt much from this build and will continue to grow our knowledge through data collection via sensors throughout the house, facade and roof structure. This allows us to continuously review performance and improve our future designs.

Some of our learnings to date include;

• Managing the house - in particular shading. While active shading provides substantially improved results over naturally grown or passive shading, it does require active management, i.e. building owners and residents who are happy to embrace that. A mix of active and passive is therefore best in many instances and ensuring some motorized automation can help to minimize required input while maximizing performance.
• Temperature and draughts: Absolute temperate can be different to perceived temperature. While 22-23 degrees may often be targeted in traditional homes, a temperature of around 21 degrees in our passive house actually feels often warmer due to the elimination of draughts, both actual and perceived, caused by varying surface temperatures. Protection from overheating with active shading and adjusting window sizes and orientations to the context of passivhaus is highly important. Hütt 01 enhances Victoria’s design and creative culture, creating a new benchmark for beautiful, innovative, environmentally conscious design and a road map for fossil-fuel-free, near-net-zero-energy buildings.

A Life Cycle Assessment (LCA) has been completed with the project achieving an A++ rating on the LETI scale (Carbon Negative). The project's LCA calculates the Whole Life Carbon impact from Cradle to Grave, covering all stages from manufacture to reuse/recycling potential. Products were selected based on sustainability credentials and/or embodied energy, e.g. recycled bricks (carbon zero), natural wood fiber insulation and mass timber structure (carbon negative), recyclable (natural oil finish) timber floors. Reducing consumption, recovering waste by recycling and giving materials/objects a second life. Inserting reclaimed sash windows into the laneway brick wall, utilizing the CLT packaging crate material as internal wall/ceiling linings are examples.

Hütt 01 has achieved Passive House Premium certification (the highest possible certification - meaning that the home can produce more energy than it needs, on top of being passive house standard). The home requires very little energy to maintain a stable indoor temperature and fantastic indoor air quality throughout the year. The house has been designed to eliminate the need for heating completely, while accepting that there may be some cooling required on a very limited number of days, at those times we are producing excess energy with the solar PV system. Heating hasn’t been needed to be put on once in the 15 months the house has been occupied - proving expectations right. The home maintains a beautiful approx 21 degrees throughout the year. Passive House: A well designed PassiveHouse just works. It is a system within which the design exists. If you haven’t experienced one, you need to come and visit us. It makes a huge difference, it is easy to manage and maintain if designed correctly, and it is just comfortable and healthy all year around. This is how we can achieve carbon zero and zero energy homes on a large scale easily.