Passive design uses a building’s footprint, its surrounding climate, and building materials to minimize its energy usage.
A passive designed home looks to reduce the buildings heating and cooling levels by using energy-efficient building strategies and solar energy to substitute the buildings remaining energy needs.
A well designed passive home, takes the following into consideration:
- For a Passive building to be highly efficient, it should be rectangular in shape with its long axis running east to west so that its longest side faces north. This will allow the building to maximise the suns exposure and ensure that installed solar panels can obtain the optimal energy required to support the needs of the building.
- Window Glazing
- Heat can be lost and gained through a windows framing jambs and the glass itself. You can choose from a range of glazing options that allow the winter heat to remain indoors while keeping the excessive summer heat out. The additional investment in glazed windows will reduce your heating and cooling costs over the life of the home.
- Operable skylights that open and close enable you to regulate the temperature in your home while allowing you to access natural light to light up a room.
- In order to reduce the amount of direct sunlight entering the rooms in summer, the depths of the eaves can be calculated according to the suns angle. In winter as the angle of the sun changes, the eaves will still allow sufficient sunlight and heat to enter and warm the rooms. Alternative shading in the form of a verandah or external blinds can achieve the same results.
- Planting deciduous trees to the north side of the property and evergreen plants to the east and west, will allow an additional form of shading. Placement of landscaping can also aid in ventilation as plants can direct the breeze through the home.
- Room Locations
- Rooms that are hardly be used during the day such as laundries, garages or bathrooms should be placed on the west side of the property to act as a buffer from the afternoon sun.
- Living areas should be placed on the north side to allow natural light in throughout the day, preventing the need to use additional lighting.
- Bedrooms should be placed on the south side of the property.
- Thermal Mass Materials
- Thermal Mass is the ability for building materials to store, retain and release heat. The denser the material and the greater the exposure to direct sunlight, the more heat the material stores. Glass captures the suns radiant heat, heavy weight construction materials like concrete slabs in the house store it and insulation helps reduce its loss. Low energy homes tend to have concrete slab floors and internal brick walls (reverse brick veneer).
- It is important that all walls, roof & ceilings be insulated as set out in the BASIX Certificate. It is vital to fill all gaps to retain wanted air in and unwanted air out. Insulation, when combined with high performance window glazing, will reduce the heating and cooling required to maintain thermal comfort.
- Windows and doors correctly positioned enable optimal ventilation. Surrounding landscaping can also help redirect the breeze into the home. External louvres on windows will allow a direct breeze to enter the room without the impact of direct sunlight.