1. Life Cycle Assessment of a New Zealand house Barbara Nebel & Zsuzsa Szalay Scion

2. “exemplar house”  Specifically designed as an example for research on residential costing (Willson 2002)  two storey design  three bedrooms and a garage  total floor area of 195 m 2

3. Building construction  suspended timber floor with foil / concrete slab on ground floor;  Light timber frame walls with fibre glass insulation, plasterboard internal lining with paint finish, external cladding weatherboard/ fibre cement/ brick;  pitched timber truss roof, flat ceiling with insulation lined with plasterboard, steel cladding/concrete tiles;  aluminium frame windows without thermal break.

4. Life Cycle Assessment Life Cycle Assessment Framework Goal and scope definition Interpretation Impact assessment Inventory analysis Direct applications: Product development and improvement Strategic planning Public policy making Marketing Other

5. Goal and Scope  Develop a generic LCA model for houses for research purposes  Compare six design alternatives  Find the environmental hot-spots  Analyse embodied and operational environmental impacts Functional unit: the Exemplar house over a 50- year period in New Zealand

6. Scenarios  Six design alternatives  Three heating fuels: wood, gas, electricity  Three locations: Auckland, Wellington, Queenstown

7. Data  Average data from Europe  for New Zealand only embodied energy and CO 2 -emissions are available (Alcorn)  Data gaps:  Dataset for carpet was based on GaBi data and a European study (Potting 1994)  Timber treatment is missing

8. Maintenance  Life time of building is 50 years  Average life time of building elements based on New Zealand and European data  Prorating was applied due to the high level of uncertainties  Life time of building element is 20 years  Number of replacements: 50/20 -1 = ? 1.5

9. Operation  Hot water, ventilation, cooling, lighting, appliances not considered  Heating energy calculated with ALF3 (BRANZ)  heating levels: 16, 18, 20 °C  heating schedules: evening, morning and evening, all day, 24 hour heating  Insulation as required by NZ Building Code

10. GaBi model

11. Production

12. Heating energy demand Evening heating, 18°C 24 hour heating, 20°C

13. Thermal mass

14. Impact categories  Non-renewable energy demand  Renewable energy demand  Global warming  Ozone depletion  Eutrophication  Acidification  Photo-oxidant formation

15. Building materials

16. Building elements

17. Wall components

18. Foundation and floor

19. Roof components

20. Life cycle energy

21. Timber/ WB/ steel

22. Environmental impacts Timber/ WB/ steel, Wellington Gas heating Timber/ WB/ steel, Wellington Electric heating

23. Transport distances 100 km - 50 km - 200 km

24. Useful life of carpet 10 years – 8 years – 15 years

25. Conclusions  For typical New Zealand heating level and schedule, materials have significant influence on life cycle results  Interesting results relating to thermal mass in intermittent heating schedule  Materials need to be looked at on component level  LCA is good tool to optimise building design  Tool can be used for other house designs based on data from quantitiy surveyor

26. Outlook  New Zealand inventory data for building materials  Insulation scenarios: NZS better and best practice  Statistical model to represent current building stock  Model retrofit of an existing house with insulation in walls

27. Futher information Barbara Nebel, PhD Groupleader Sustainability Framworks Sustainable Consumer Products Private Bag 3020, ROTORUA, New Zealand Phone +64 7 343 5637 Email: Barbara.nebel@scionresearch.com