The Spring Hill “Enviro-Cottage” was designed using passive solar design principles to ensure the sun’s heat, light and local breezes contribute year round to the cottage’s comfort. The architect partner Steendyk spent time on site, identifying how the sun moved across the property during the day and through the seasons, and from where prevailing winds and breezes come from.
The passive solar design objective is to ensure all rooms are kept to a comfortable temperature all year round - between 18ºC - 27ºC. This ensures comfort levels so there’s no need for artificial heating or cooling devices.
The following passive solar elements are part of the design:
Orientation
Introduction of a rear “solar pod” and internal courtyard rather than simply extending the existing dwelling – “cut and separate”, rather than simply lift and extend. This opens the main living area to the northern aspect. This design also minimises the building depth to encourage cooling summer breezes.
Kitchen/dining double height space with glass ceiling, allows northern light to penetrate rear living spaces in winter. External sun louvres provide shading in summer.
Western aspects protected by use of fencing, masonry and perforated feature metal sheeting. Minimal windows (for ventilation purposes) including high under eaves.
Thermal Mass
Feature burnished concrete floors in living room, kitchen and dining room and exposed concrete walls provide thermal mass to collect and redistribute heat during winter months.
Shading elements (wide solar louvre overhang and external sun louvres) protect thermal mass elements in summer.
Ventilation
- Louvres strategically located in existing dwelling and new pavilion - draw natural cross ventilation, expel warm air in summer.
- Doors and windows have been placed on different sides of each room, so that when open, a cooling breeze will blow through the home
- Ceiling fans included to help circulate air
- Windows and doors seals checked and draught-excluders fitted
- Whirlybird re-used to extract roof space heat
- Rear of original house and front of new “solar pod” can be completely opened through use of sliding stackable doors
- Laundry/garage space allows cross ventilation through use of timber battens to aid the clothes drying process
- Double height dining area acts as a thermal chimney, drawing out hot air generated in the kitchen and dining areas
Windows
Thermal glass, equivalent to double glazing, used in all new windows and glass doors ensure trapped winter heat is not lost during evenings.
North facing windows of “solar pod” are large to permit solar access in winter, but shaded by large eaves and metal screens to provide shade in summer. Minimal use of south facing windows. East and west facing windows are well shaded by verandah, metal screening and fins.
Shading
Shading is most effective when it stops the heat before it hits glass windows and doors. Metal screening, large solar louvre overhang and external sun louvres provide shading for large areas of glass and thermal mass.
Solar louvre overhang on new “solar pod” shades in summer but allows winter sun to penetrate deep into the pavilion floor plan to warm the thermal mass (burnished concrete floor) for natural winter heating. External sun louvres over glass ceiling provide sun control – permitting sun penetration in winter and shading the glass ceiling in summer.
Automated system with manual override function provides control.
Insulation
- High performance insulation from Higgins included in wall cavities, the roof and ceilings
- Light-coloured roofing material and external paintwork to reflect heat, helping keep the house cool.
The passive solar design principles outlined above can be seen in action when the Spring Hill “Enviro-Cottage” opens for public viewing in 2009. Open day details will be posted on www.envirocottage.com.au and announced on ourbrisbane.com
