Guideline for the Size of Windows

In planning the size of windows, the optimum daylight level relative to the purpose of the room must be the deciding factor. For instance, building regulations require a minimum window area of 1/8 of the floor surface area for living rooms (see table).

Window size54/83
Surface area of the light admission (M²)
Room size (M²)22 - 33 - 44 - 56 - 791113

Large windows make living rooms more comfortable.

The window width in secondary rooms can be chosen according to the distance between the rafters. Generously wide windows in living rooms can be achieved by the inclusion of rafter trimmers. Steeper roofs need shorter windows, while flatter roofs require longer windows. Roof windows can be joined using purpose-made prefabricated flashing, and can be arranged in rows or in combinations next to or above one another.

roof windows

This guideline for the size of windows is taken from the book Architects’ Data written by Ernst and Peter Neufert, whereas this book has become the guideline for architecture college students in the world.

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  • How to Make the Most Comfortable Bedroom | i-deaHOUSE May 1, 2018 at 12:30 pm

    […] bedroom. It reaches the maximum level of comfort because you can make the windows big (see: Guideline for the Size of Windows) without worrying about your bedroom ever getting too much sunlight (considering the sun rises in […]


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