The disadvantage of insect netting is the reduction of ventilation capacity. Therefore Holland Gaas has engineered a meshsystem to minimize the impact of the air ventilation reduction. TNO, a Dutch Research Organization, performed an extensive research according to this issue.
Holland Gaas also has another ventilation advantage: The harmonica shape generates much more ventilation then plain netting. The larger surface causes more ventilation. (Beware that there is an optimum in the numbers of the sheets concerning the ventilation.)