Cool temperate climates
In Australia’s cool temperate regions it’s worth taking passive solar design seriously. Where that is possible, the best of all approaches is incorporating reverse thermal mass. With walls well insulated on the outside, the benefits of free solar energy are combined with obtaining the best value from the artificial heating which is required at least some of the time. Where a poor orientation precludes winter solar gains, concentrate on well insulated walls and roofs. Thermal mass in a slab on ground is almost always an advantage, but where site conditions dictate suspended floors they should be well insulated. The energy conservation weak spot for both winter and summer is over glazing.
Orbit Homes has produced a 6-star display home at the Aurora estate in Melbourne. Its compact size, disciplined use of glazing and overhangs, as well as visibly lightweight cladding is consistent with design ideas outlined in the table below. While built in Melbourne, these design strategies are very suitable for Hobart.
[ back to map ]
| Design elements | Design essentials | Best practice design options | Recommended James Hardie materials |
| Siting | Minimise external wall areas (especially East and West). | Site new homes for solar access and protection from cold winds. Exposure to cooling breezes in summer is still desirable. | |
| Sub-floor and floor | Some thermal mass is desirable. Consider slab on ground where possible. | Insulate slab on ground edges. If building on sloping sites using bearing and joist construction in steel or timber, insulate the sub-floor and reduce sub-floor ventilation to the minimum. In addition, minimise ventilation cavities through walls from the sub-floor to the roof to prevent heat leakage. | |
| Roof | Bulk insulate ceilings. | sub-floor ventilation to the minimum. In addition, minimise ventilation cavities through walls from the sub-floor to the roof to prevent heat leakage. | |
| Walls | Use reflective insulation to keep out heat in summer and bulk insulation to keep heat in during winter. | Use reflective sarking under tile roofs. Under metal roof sheets, use insulation blanket with downward facing foil. | Any James Hardie cladding material in combination with bulk insulation and taking care with vapour-proof membrane placement. |
| Openings | For passive solar design, maximise north facing walls and glazing, especially in living areas. Minimise east, west and south facing glazing. Place openings for effective summer ventilation and night-time cooling in summer. | Use reverse mass construction and passive solar principles where possible. | |
| Clip-ons | openings for effective summer ventilation and night-time cooling in summer. | Use double glazing where possible, with insulated frames and/or use heavy drapes with sealed pelmets to insulate glass in winter. Use door and window air seals, and provide airlocks to entries. | James Hardie eave lining materials like Versilux lining and HardiGroove lining for soffits. Consider using HardiPanel compressed sheets or Scyon™ Trim battens in adjustable window shading systems with appropriate design and detailing. See examples in The Smarter Design Book at http://jameshardie.com.au/smarterdesign |
| Landscape elements | Design eaves of correct proportions for summer shade to both walls and glazing, or use adjustable shading. |
[ back to map ]