White & terracotta Flueless Gas fire Air vent (H)195mm (W)270mm.The purpose of an air vent is to protect from rain vermin etc. entering while allowing a measured amount of air to enter for combustion purposes. All flueless gas fires and stoves require a minimum ventilation of 100cm². Manufacturer\'s tests have shown that the Century 100 vastly reduced the speed of air recorded flowing through this product due to the internal baffles repeatedly changing the direction.