Direct answer: control heat, not only insulation
In warm sunny areas, the goal is to reduce excessive solar gain while keeping light and comfort.
Solar control glass
South and west façades may need solar control glazing to reduce overheating.
Colour and exposure
Dark colours and exposed façades require technical review, especially in very sunny areas.
Shutters and external shading
External protection often works better than relying only on glass. The shutter box must also be insulated.
Common mistakes
Ignoring orientation.
Thinking only about winter.
Not protecting large west-facing openings.
Using one solution for every façade.
Practical recommendation
Choose glass and protection by orientation, not only by room size.