Encouraging ventilation is an important aspect of passive cooling in a home. At Energy Rating Perth, our clients are always complaining of high electrical bills due to their cooling load. An energy assessment done by our energy assessors has usually resulted in the conclusion that the building is experiencing inadequate ventilation.

Ventilation whether mechanical or natural is an essential factor in maintaining indoor thermal comfort and therefore reducing the energy usage on air conditioning. In hot and/or humid climates, the air movement helps reduce excessive moisture from the air causing a cooling effect. For efficient natural ventilation, the wind patterns/speeds, size/height of entry and exit points need to be studied and implemented. Inadequate ventilation can result in a stuffy environment with stale air, a lack or excess of moisture and even health concerns for the inhabitants. This can result in a drastic building defect which will result in high energy costs to regulate a comfortable internal environment. The best method would be to incorporate ventilation design appropriate to the local climate at the time of design by:

  • Encouraging cross ventilation by controlling entry and exit size of the openings.
  • Placing highlights to get rid of the rising heat due to the stack effect
  • If space allows, the use of atriums with ventilation points at the top or even courtyards
  • Selecting an appropriate window that allow adequate ventilation such as a vertical sliding window
  • Use of screens to allow full opening of the window


If the building does not have cross ventilation incorporated into the design, the use of mechanical ventilation such as fans, exhaust fans and particularly ventilators for a roof space can improve a building’s ventilation. There are also retrofit products available that can greatly help with maintaining a steady indoor ventilation. Such products include solar power ventilators that for heating use fresh filtered warm air trapped under your roof throughout your home and for cooling remove the same trapper warm air to avoid heat build-up.

Contact Energy Rating Perth today for more information!