Results Summary
| Impact Area | Total CO2e / Year / occupant (kg CO2e) | % Saved Against Benchmark | eTool Medal |
| Embodied Carbon | 851 | 5 % |  |
| Operational Carbon | – 1,251 | 140 % |  |
| Total Carbon | – 400 | 110 % |  |
Project features
Design life
The extended design life of 70 years was a result of low redevelopment potential due to the high quality design and sustainability features. It is 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 spread across a longer period of time, contributing to a lower embodied carbon impact per year.
Average occupancy for a 3 bedroom house over its service life is 2.46 occupants. eTool have identified that occupancy could be increased with an extra bedroom when analysing total enclosed area. Increasing the number of occupants will improve overall carbon performance when using a kgCO2/year/occupant functional unit.
Operational Energy
Outstanding operational energy performance achieving an eTool Platinum medal with 140% savings when compared to residential benchmark. Overall performance was a result of minimal energy input requirement for thermal control because of the 10 stars energy rating, use of solar energy for hot water in combination with electric storage system, high natural lighting level and LED lighting, energy monitoring and a 5kW solar PV system.
The location the house is in Geraldton doesn’t have natural gas available so two of eTool’s recommendations could not be implemented at this stage: gas boost for the hot water system and gas cooking. Although the house will benefit from solar electricity, use of gas still provide better environmental results for a house that is connected to the SWIS (South West Interconnected System) electricity grid. More details can be found here.
Thermal Performance
The 10 stars energy rating result was a combination of a well designed solar passive home with aluminium and timber frame windows, light weight timber frame insulated walls, reverse brick veneer walls for thermal mass, high performance ceiling insulation, cross ventilation and fixed shading. Only fans will be used to provide necessary cooling load and no heating system is required in this design.
Renewable Energy
David and Mark have chosen to install a 5kW solar system. Over the expected life of the building, the solar systems (accounting for re-installations) will have a net saving of over 497t CO2e! The main advantage of a solar system is that it offsets carbon intensive electricity grid.
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.
Use of eTool at design phase
Use of fly ash in concrete mix could not be implemented because the slab was already in place while eTool performed the LCA. Other recommendations to further improve the overall carbon footprint of the house were considered including internal clothes line to reduce clothes drying energy and customised fridge space with increased ventilation. More details about ventilation of fridge space can be found here.
This is a good example of how important it is to consider eTool while in the design phase to be able to not only quantify but also achieve best possible outcomes.
Additional Features
- Energy monitoring to allow occupants to understand what appliances and devices are demanding the most energy (electricity) and adjust behaviour accordingly.
- Use of local assembled windows.
- Use of recycled timber and sustainable sourced timber.
For more information about the development, visit the development’s new website Footprint Free On Fitzgerald or like them on Facebook.
This assessment was conducted by Henrique
