Window to Floor Ratio (WFR)
Technical Clarification Number
South African design teams generally refer to Window to Floor Ratio (WFR). EDGE has therefore introduced WFR into the building Design page and the Window to Wall Ratio section. To change the WFR, the user must modify the WWR. WFR cannot be modified directly in EDGE software.
By changing the WWR, the area of windows changes in the software calculations.
This automatically modifies the WFR as follows: 𝑊𝐹𝑅= Total Window Area/ Total Floor Area
So, since the floor area remains constant (from the input in the Design page), the window area may be amended by changing the WWR.
WWR and WFR are not directly proportional, although when WWR increases the WFR also increases. However, a conversion factor is not possible since the dependent variables are not the same for WWR and WFR.