In radiators, the hot water runs top down through the various components, which are made of steel, aluminium or cast iron. In turn, these elements as a group work together to make the heat go up and warm the surrounding air.
The whole process produces a combination of:
Radiant heat : the panels that radiate the heat
And convective heat : the heated air that rises up and consequently attracts cooler air to the radiator.
On the other hand, the hot water in a convector radiator is circulated through a tube, which is surrounded by small fins. These fins act to increase the contact surface with the surrounding air.
As with a regular radiator, the hot air rises up and attracts cooler air to the appliance. In some types, a ventilator can act to accelerate this process.A convector radiator chiefly delivers heat through convective heat.