External Roller Blinds are the most effective way of eliminating direct heat and sunlight into a building. Architecturally external Roller Blinds have huge benefits in energy ratings. Therefore, increasing the effectiveness of air conditioning and heating systems.
Up to 90% of the sun’s heat can be kept out depending on the fabric type selected.

The operation is either manual crank handle or more commonly motorization. They can be completely automated in conjunction with sun and wind sensors.
The fabrics can be varying degrees of sheer screens or block out. (Soltis)
External Roller Blinds can eliminate the requirement for any internal window furnishings.