If a screen installation is closed, this will result in differences in temperature above and below the screen. Above the screen, the air will cool down considerably and this airstream will gather in the greenhouse ridge. Then, the cold air descends by the sidewalls and drops down towards the crop. Because of this airflow, not only do temperature differences occur, but there are also differences in CO2 and relative humidity. This has a negative impact on both the crop and on energy consumption.