The purpose of this study was to find out the local intensity and extent of doorway draughts, the functioning of air curtains, and the variation of the neutral pressure levels in 18 industrial premises. The doorway draught can reach the whole workspace and all the employees. At the doorline, close to the doorway, the thermal conditions can be even harsher than those outside. Air curtains significantly decrease the fluctuation of the temperature at work sites, but the functioning of the same type of air curtain varied substantially between the buildings. It seems to be impossible to estimate the height of the neutral pressure level and the air balance without measuring the pressure difference across the envelope with the ventilation both on and off. The work areas susceptible to the air flows caused by using large doors should be increasingly considered as an entity in overall planning.