As people spend around 90% of their time indoors, good ventilation of buildings is essential to maintain good health. Additionally, ventilation has a significant impact on the quality of the building e.g. in very tight buildings, there is a greater risk of mould and damp if the air is not changed regularly. This paper assesses the impact of different types of ventilation systems in homes and schools on the occupant's health. A literature review has also been conducted to assess the influence of ventilation on health.