Balanced flue gas fires, also known as closed combustion gas fires, are highly efficient appliances that are connected to the outside atmosphere via a concentric flue. Air is drawn in from outside for combustion purposes, with waste gases expelled back out through the flue and out of the building. All balanced flue gas fires are room-sealed and have a glass front, making them attractive as well as comfortable to use. Thanks to the appliances being sealed, oxygen levels in the room are not affected by the fire, making them ideal for those who suffer from respiratory conditions. balanced flue gas fires are a great way to heat your home efficiently and safely.