Solar over-heating can be worsened by the inclusion of large areas of rooflights, however the heat from the sun is also likely to be passing through the rest of the roof and wall cladding and contributing to this and adding to any internal heat gains. For most of the year, the heat from the sun passing through the rooflights is a good thing and can significantly reduce the heating required.
Rooflights that have been covered over cannot usually be easily uncovered and recovered to suit the changes in weather, and any coating applied to the rooflight may only have a short effective period. The preparation and application also risks damage to the rooflights and foreshortening their service life. A better approach is to consider improving the ventilation provision to the building.
