Passive Butterfly

Armadale heritage house recognised for sustainability features

One of the first Australian homes with heritage planning restrictions to be renovated according to passive design principle goals butterfly roof was shaped to increase solar gain in winter, and protect it in summer

EME Design received a commendation in the BDAV’s 2018 Building Design Awards in the Best Environmentally Sustainable Design-Residential category for their ‘Passive Butterfly’ project.

Amongst the recognition achieved for this exemplar retrofit project includes ‘Best of the Best’ as well as Single Dwelling (Alteration or Addition) in this year’s recently announced Sustainability Awards, and Best Sustainable Design in the NABD 2018 Awards.

The Armadale (VIC) heritage house project – a south-facing extension transformed into a passive house – was named after the butterfly roof that was shaped to increase solar gain in winter, and protect it in summer.

Behind this traditional heritage weatherboard façade is a surprisingly sustainable renovation and addition. Bright and airtight, the Passive Butterfly opens its wings in a contemporary form that is as high-performing as it is handsome.

With part-Scandinavian heritage, the clients were passionate about efficient building design, and sought the highest standard of passive build they could achieve on the site – no mean feat when working with an existing heritage home. Exacting insulation measures and passive design principles, including a heat recovery system, ensure the building’s temperature fluctuates by just 1.5 degrees Celsius for 95 per cent of the year. This minimises the need for heating or cooling, improves air quality, and ensures the building outperforms many high-rated Nationwide House Energy Rating Scheme (NatHERS) rated homes.

The asymmetrical butterfly roof form brings light to the rear living areas and heats the rammed earth internal walls – the backbone of the building’s thermal mass – in winter. The slope of the rear roofline also creates optimal growing conditions in a once sun-starved, south-facing backyard. Rainwater is captured too, and stored in two partially submerged 5,000 litre tanks hidden below the raised rear deck. This water is used for toilet flushing and for garden irrigation.

Natural materials of timber and rammed earth were chosen for internal construction and joinery, both for their neutral colour palette and for their durability and low embodied energy.

The building makes excellent use of a 430sqm site, allowing for three bedrooms (including a master bedroom with walk-in-robe and ensuite), a central bathroom, and a generous home office, in addition to the kitchen, separate dining and sunken living room.

Out front, the heritage building features have been preserved, with an upgrade to triple-glazed, airtight windows for the street-facing bedroom and home office. Here, the major changes have been reserved for landscaping. An oversized central tree was removed from its central position, making way for indigenous plantings of gums and native habitat surrounding a feature billabong. In practical terms, this small body of water supports overflow management, but it has also proved its magnetic appeal for neighbourhood kids, who regularly stop by in search of local wildlife. The indigenous landscaping choices have also broken the otherwise traditionally European-style plantings of the neighbouring gardens.

Luke Middleton of EME Design is thrilled with the outcome achieved for his clients: “This building is super-efficient, both in plan, in thermal qualities and in health.”

“They’ve got a fantastic home that serves their family. It’s adaptable and robust for the future and adds to the wildlife corridor,” Luke says.


Designer:  EME Design Pty Ltd
Builder:  Ridge Developments Pty Ltd
Photographer:  Amorfo

About EME Design

EME embodies the integrity of intelligent, efficient design. They create beautiful, sustainable buildings inspired by a process of dialogue and exchange. When EME looks at a space, they see the potential for a balanced relationship between innovation and function. For more than 15 years, they have been working closely with their clients to create award-winning projects that above all provide enjoyment, beauty and efficiency.

‘Passive Butterfly’ designed by EME Design
‘Passive Butterfly’ designed by EME Design - Images: Amorfo