Condensing vapor can transfer heat. This principle is being applied in the vapor phase soldering process to solder boards in a reflow-type process. Water vapor can not be used, since very special requirements are for on the vapor. The vapor used may not be corrosive, it may not be conductive, and it has to allow high vapor temperatures without high pressures. A suitable process media are fluorocarbons, with selectable boiling points of between 180°C - 260°C. In contrast to normal convection (process medium gas) the heat transfer to the product to be soldered is up to a factor of 10 faster. An alternative term is condensation soldering.