Pam’s House

Located in rural dairy country near Margaret River and surrounded by beautiful forests, Pam’s House is a custom design by Paul O’Reilly from Archterra. Paul is a passionate mountain biker who has worked as an architect across a range of climate zones from the tropical northern territory to the temperate South West WA for over 15 years and considers “sustainability” to be an intrinsic part of any good design. Archterra which has been running for the last 6 years allows Paul to offer clients a personalised service where carbon footprint is considered a key driver in the design process, resulting in a design response that is both environmentally and architecturally creative. Working with passive solar design strategies, appropriate material selection and energy efficient hot water, lighting and heat solutions, Paul aims to minimise a project’s impact on the grid. As in the case of Pam’s House, Paul tried to combine Pam’s interest in ‘doing her bit for the planet’ and interest in energy efficiency features with a desire for comfort and a little luxury in her retiring years. Our assessment was completed in January 2013 and construction is due for completion in August.

  • Date: May 2013
  • Architect: Archterra
  • Location: Margaret River, Western Australia

Results Summary

Impact AreaTotal CO2e / Year / occupant (kg CO2e)% Saved Against BenchmarkeTool Medal
Embodied Carbon 77114 %etool_bronze_medal
Operational Carbon-375112 %Platinum_medal
Total Carbon 39690 %

Project features

Design life

The extended design life of 90 years was a result of low redevelopment potential, due to the high quality design and its location in a semi rural area. It’s well known that design life is largely affected by redevelopment potential rather than structural integrity of the building. The environmental impacts caused by the materials and their transportation, assembly and maintenance of the building will benefit more people during a longer period of time, contributing to a lower embodied carbon impact per year per occupant. On the other hand, the recurring maintenance impacts on a long last building highlighted an area of potential improvement.


Use of low embodied energy materials such as plantation-grown timber framed construction combined with rammed earth walls to increase thermal mass, reduce finishes and provide a natural and stylish look. Use of fly ash in concrete mix for slab and foundations to reduce concrete carbon intensity.

Operational Energy

The Platinum Medal in operational carbon savings is a result of use of fans and slow combustion wood for thermal control, solar hot water system, high level of natural light combined with LED lighting along with energy metering dramatically reduced the energy requirement for the home. Energy efficiency measures were considered before implementing renewable energy from solar PV system. Energy monitoring allows occupants to understand what appliances and devices were demanding the most energy and adjust their behaviour accordingly and payback period is usually less than an year.

Thermal Performance

The house was designed to achieve a 6 stars thermal performance in Energy Rating NatHERS. Additional features to improve the overall carbon footprint of the house was redirected to hot water system and renewable energy systems for example. eTool also provided feedback and comparison of different insulation types and combinations, which resulted in glasswool bulk insulation and foil faced foam board being utilised to provide a very high insulation value with low embodied carbon  and long design life.

Renewable Energy

Paul and his client have chosen to install a 3kW solar system which will meet all his client operational energy needs and have a net saving of 320t CO2e over the expected life of the building (accounting for re-installations). The system will generate more electricity than the occupants need to offset the use of natural gas used for water heating and cooking. Solar PV has a high embodied carbon component and without it the design would have achieved a better “Embodied Energy” rating. However, the substantially reduced “Operational Impact” due to the renewable energy input offsets this increased “Embodied Impact” many times over during its design life.

Additional Features

For more information about Archterra’s design work, read ABC’s article about Paul’s own home design here or get in touch with Paul.

This assessment was conducted by Henrique