Results Summary

Impact Area Total CO2e / Year / occupant (kg CO2e) % Saved Against Benchmark eTool Medal
Embodied Carbon 714 54% eTool Silver Medal
Operational Carbon 109 96% etool_plat_medal
Total Carbon 823 80% etool_gold_medal

Project features

It is observed through the LCA modeling that the following areas have the greatest impact to the overall environmental footprint of the building:

Solar Passive Design

The design incorporates fundamental passive design principles; bedrooms to the east, to wake with the sun and be cool in the evenings; living areas to the north with good northern glazing, to allow winter sun deep into the building envelope; and utility areas to the west, so they can absorb the strong summer sun in an area that is infrequently occupied. Shadow modelling allowed us to optimise eave depth and offset so in summer solar radiation is blocked. The final house design is 125m2 on a 330m2 block, which is small by Australian standards but building smaller means less expenses upfront and less ongoing living costs.

Operational Energy

Sustainability House simulated thousands of wall, insulation and window combinations to reach the highest NatHERS star rating possible for the building at the agreed budget. 3D modelling and sun path analysis assisted in the design of shading devices, eaves depths and window locations.

The project was designed for reduced energy demand and achieved a high thermal performance rating of 7.5 stars with ceiling fans as the cooling method, high efficiency LED lighting and a solar PV system to produce electricity for water heating and cooking. A 3.5 kW solar system combined with battery storage (to be installed late 2016) will further enhance the 96% savings in operational energy with a target of reaching net zero carbon in operations.

Testing Of Performance After Completion

The building was air pressure tested and assessed using thermal imaging to ensure good build quality. A monitoring system was designed and installed to collect data on actual building performance, which will be compared against the predictive performance from the modelling software. The monitoring system tracks internal temperature and humidity, energy consumption and solar electricity production. Also a weather station on the roof monitors external temperature, humidity, wind direction, speed and rainfall.

Materials and Construction

The house was built using a Structural Insulated Panels (SIP) walling system, to make the build simpler and quicker, which resulted in the building being locked up in less than three weeks.

Optimised construction time (total of 16 weeks) resulted in less impacts from trade staff transportation to site. A careful selection of materials guaranteed higher thermal performance and durability, and lower maintenance requirements. Materials list included:

  • Double glazing,
  • Structural Insulated Panels (SIPs),
  • Weathertex cladding,
  • Light-coloured Bluescope Colorbond Roofing,
  • Low e Double-Glazed Windows,
  • Polished concrete floors,
  • R6 Earthwool insulation was used in the ceiling,
  • One wall was filled with phase change material to increase thermal mass,
  • Recycled interior feature Brick wall,
  • Sisal carpet,
  • Non VOC paints primer, undercoats and sealers on the ceilings, walls and woodwork to eliminate toxins and improve air quality,
  • Bamboo Deck,
  • Recycled Paper bench tops,
  • Rainwater tanks of 7,000 litres,
  • Reduction of waste through prefabricated wall system,
  • Low maintenance garden, lots of native and drought tolerant plants, with plans for a vegie and herb garden.

 

This assessment was conducted by Aida Leon of Sustainability House and certified by Tom Beckerling from eTool.