The oldest type of liquid heating is sectional radiators. Sectional radiators are cast -iron, bimetallic, steel and aluminum. Thanks to modern design, these devices have acquired a new life. Cast iron radiators are valuable in that the flow of heat goes through radiation and is evenly distributed around the room, but the big weight is minus. Aluminum radiators, light with a perfectly flat surface, high heat transfer. But sensitivity to chem. The composition of the water, often leads to the destruction of the radiator, sensitive to hydrauliciate. But bimetallic radiators are similar to the advantages, do not have practically disadvantages.