Energy efficiency - Passive design

Heating and cooling

Carefully select the orientation of the building to make use of solar gains. A southerly orientation can allow maximum sunlight and hence warmth during the winter and during the summer the sun can be tempered by blinds, shading systems, balcony overhangs or even deciduous trees to prevent overheating.

Place the frequently used rooms, requiring most heating on the south side of the building (e.g. living room in a house)

Rooms that do not benefit from sunlight can be placed to the north of the building (i.e. hallways, bathrooms, utility rooms, stores) and can have smaller windows to minimise heat loss.

Good insulation in walls, roof and floors keeps the heat in during winter and out during summer.

Thermal mass is the ability to store heat from the sun or provide a heat sink to assist cooling. Use of thermal mass within a building either allows the sun to be ‘soaked up' during daylight hours and then released into the building at night. Alternatively the thermal mass can be situated away from any direct heating in order to ‘soak up' any heat within the building and release this overnight when conditions are cooler. Thermal mass prevents overheating during the summer and avoids cold conditions during the winter.

Passive stack ventilation can be used to allow natural breezes into the buildings. These breezes can help cool down the buildings and provide fresh air. For large buildings the stack effect can be used (due to the fact that hot air rises) i.e. a solar chimney draws air out from the building through the chimney stack.

 

Lighting

A southern orientation also provides maximum daylight for key areas however a careful balance between light penetration and glazing / shading is required to ensure heat loss/gain is managed.

 

Ventilation

Ventilation of a building is critical in summer to provide a cooling effect. The building does not need to directly face the direction of the breeze, as long as the breeze is directed in and out of the building (through windows or vents etc).

Clear ventilation paths are required through the building, with regular openings on opposite sides of each space. Cross ventilation works most effectively with a building depth of less than 15m.