Ventilation is the active process of “changing” or replacing air to regulate temperature and moisture. It should always occur under controlled conditions, by opening windows or with ceiling or exhaust fans, NOT through gaps and air-leakage. Ventilation is important to support the ability of thermal mass to absorb and release heat in order to regulate the indoor temperature.

Ventilation serves one primary purpose which is to maintain good indoor air quality – primarily for us to breath. Since we spend more than 90% of our lives inside buildings, this is important for our respiratory health. But there are other benefits too.

Adequate ventilation should:

  1. Remove harmful contaminants such as fine particles, and organic chemicals from cooking & carbon monoxide and nitrogen dioxide if using a gas hob.
  2. Remove excess moisture generated from household activities such as cooking, showering and even breathing. The average family can produce eight litres per day.
  3. Remove carbon dioxide
  4. Introduce oxygenated fresh air from outside – not a dusty roof space.
  5. Replace at least 35% of the internal volume of air every hour (NZS4304 the standard for ventilation for acceptable indoor air quality)

Traditionally we have relied on natural ventilation – opening and closing windows to meet our ventilation requirement. This can be haphazard as it relies on fickle human nature, suitable weather and of course which windows happen to have been opened. Mechanical ventilation is looking more and more to be the way of the future – with either continuous extraction – or better still balanced ventilation which physically removes moisture and brings in fresh air from outside.