Collective buildings, also called multi-apartment buildings, can be heated individually by installing a separate heating appliance for each apartment. The most common choice is a gas boiler which provides the whole apartment with heat and hot water. There are solutions that remove combustion products through the walls of a building but it damages the facade and the health of the residents. Collective chimney system is made of stainless steel and is lined through the roof of the building. The system effectively eliminates combustion products into the atmosphere.