These modern built-in fires are fitted with a patented filter made of ceramic material with a micromesh structure, through which the flue gas is passed before leaving the fire and where the particulate is incinerated by the high temperatures. Thanks to the enormous heat reflection, the ceramic filter ensures a better combustion, which results in a higher output. The sponge-like structure of the filter traps glowing fragments and thus prevents chimney fires. In addition, the filter provides very good insulation, which means that the temperature in the chimney will be lower, making the surrounding area warmer, which in turn further increases the heat output