Why is there fogging on the outside of the glass?

Fogging may occur on the outside of the glass. Common causes are:

  • The relative humidity of the location. The higher the humidity, the greater the risk of condensation/fogging.
  • The U-value or insulation level of the panel. The better the panel is insulated, the less heat is applied to the outer pane. The surface is then cooler, increasing the risk of fogging on the outside
  • The temperature inside the room.
  • Blockage, i.e. heat from the panel cannot radiate freely into the sky.

Exterior fogging is not a sign of a defect in the pane.