Daylight autonomy is determined by location, orientation, windows shade and position as well as Window-to-floor ratio and Visible Light Transmission of the glazing. The following aspects are fundamental to achieve an effective balance between all these variables:
Consider the relationship between openings and space: Window-to-Floor Ratio
The calculation of the relation between the area of the openings and the area of the space is called Window-to-Floor Ratio (WFR) and is obtained by dividing the total area of the openings by the total area of the space associated with them. This factor helps define the number of openings that will work effectively in each space of our project. It can also guide things like the openings' size, location, and type of glazing. In some countries, like France, it is mandatory to have at least a WFR of 17% for all new residential buildings.
The WFR value must be multiplied by the value of the Visible Light Transmission of the chosen glass (VLT), explained below, to ensure that the design moves within the thresholds that ensure certain effective levels of visual comfort (usually a value above 0.15).
Decide the amount of light that must pass through the glass: Visible Light Transmission
As described above, the relationship between the openings and the space must be complemented with the Visible Light Transmission (VLT), which corresponds to the amount of visible light that passes through the glass. Glass with VLT of 50% allows 50 percent of light through and blocks the remaining 50 percent. With this, we can decide to incorporate large openings in our project and at the same time control the amount of light that passes through it, while also adding protection against UV rays and glare.