A method for condensing vapours under vacuum, wherein the vapours are produced in the production of polyesters by means of a polycondensation reaction of dicarboxylic acids or ester derivatives thereof and a diol, and wherein water, diols and solids are contained in the vapours to be condensed, wherein the condensation method is carried out in a device for condensing vapours under vacuum, the device comprising at least one spatial condensation region connected to a vacuum apparatus for generating a pressure below atmospheric pressure, with at least one spray condenser and at least one cooling means for condensing the vapours at a pressure below atmospheric pressure, the condensation taking place via a spray liquid as the cooling means introduced into the spray condenser; wherein the device comprises at least one spatial collection region for condensate and solids with at least one collection container connected to the at least one spatial condensation region, wherein the collection of the condensate takes place in the at least one collection container in the collection region; wherein the condensation of the vapour in the at least one spray condenser takes place in the condensation region with the spray liquid having a temperature of 10-80 °C, and wherein at least one condensing and collecting unit formed from the at the at least one spatial condensation region and the at least one spatial collection region is maintained at a pressure between 0.1 - 100 mbar, characterised in that the at least one spatial condensation region and the at least one spatial collection region form the at least one condensation and collection unit within a vacuum-tight housing, whereby a barometric dipping is not required, so that the collection container also has a pressure below atmospheric pressure; wherein the condensation method is carried out in a device for condensing vapours under vacuum, the device comprising at least one spatial condensation region connected to a vacuum apparatus for generating a pressure below atmospheric pressure, with at least one spray condenser and at least one cooling means for condensing the vapours at a pressure below atmospheric pressure, the condensation taking place via a spray liquid as the cooling means introduced into the spray condenser; wherein the device comprises at least one spatial collection region for condensate and solids with at least one collection container connected to the at least one spatial condensation region, wherein the collection of the condensate takes place in the at least one collection container in the collection region; wherein the condensation of the vapour in the at least one spray condenser takes place in the condensation region with the spray liquid having a temperature of 10-80 °C, and wherein at least one condensing and collecting unit formed from the at the at least one spatial condensation region and the at least one spatial collection region is maintained at a pressure between 0.1 - 100 mbar, characterised in that the at least one spatial condensation region and the at least one spatial collection region form the at least one condensation and collection unit within a vacuum-tight housing, whereby a barometric dipping is not required, so that the collection container also has a pressure below atmospheric pressure;