Hekis

Acrylic is an organic material which absorbs water in molecular form. This means that water can penetrate the pane and raise the humidity in the double-glazing area. If the external temperature drops, the air between the two panes cools down. The superfluous humidity settles on the coldest side, that is, on the inner side of the outer pane.

An effective way to get rid of condensation is to ventilate the interior of the vehicle in order to reduce the humidity. Humidity is influenced by the air circulation. One could also raise the interior temperature. When cold air is heated up, it can thus absorb vapour. Therefore, your Rooflight is not defective should there be condensation between the two panes. You should just have a little patience until the condensation disappears.