**About Window to Wall Ratio Calculator (Formula)**

A Window to Wall Ratio Calculator is a tool used to calculate the percentage of a building’s exterior wall that is comprised of windows, compared to the percentage of the wall that is made up of solid material. This ratio is an important consideration in building design, particularly in the areas of energy efficiency and building performance.

**The formula for calculating the window to wall ratio is:**

**WtWr = GWA / GEWA**

**where:**

- WtWr: the window to wall ratio, expressed as a percentage
- GWA: the glazing window area, or the total area of all windows in the building (in square feet)
- GEWA: the gross exterior wall area, or the total area of all exterior walls in the building (in square feet)

To calculate the window to wall ratio, the total area of all windows in the building (GWA) is divided by the total area of all exterior walls (GEWA), and the result is multiplied by 100 to express the ratio as a percentage.

For example, if a building has 500 square feet of windows and 2,000 square feet of exterior walls, the window to wall ratio would be:

**WtWr = 500 / 2,000 x 100 = 25%**

This means that 25% of the building’s exterior wall area is made up of windows, while the remaining 75% is comprised of solid material.

The window to wall ratio is an important factor in building design, as it can have a significant impact on the building’s energy efficiency, thermal performance, and overall aesthetics.

Buildings with a high window to wall ratio may have increased heating and cooling costs, as more heat is lost through the windows, and may require more careful consideration of shading and glazing options.

On the other hand, a lower window to wall ratio may make a building feel more enclosed and less welcoming to natural light, which can negatively affect the building’s indoor environment and overall occupant satisfaction.