The louvres ensure that fresh air can enter from outside and that polluted or overheated indoor air can be evacuated . Louvres are frequently used in the residential sector as an exterior finishing for an extraction hood, airing cupboard or a home air-extractor fan. Louvres provide great added value as night cooling to prevent the overheating of a building. This means that they are essential to keep buildings functional and livable. The thermal mass of the building is cooled down and the indoor temperature is kept stable during the day. Night ventilation can be achieved by installing specific louvres on the evacuation sides of the building
