From GridLAB-D Wiki

door_area – Area of doors on house.

## Remarks

The door area is used to calculate net_exterior_wall_area, envelope_UA, and house_content_heat_transfer.

This is an automatically calculated value, not a variable that the user may set. It is calculated by:

door_area = number_of_doors * 3.0 * (78.0/12.0)

## Default

Using default values:

[math]4 \cdot 3 \cdot \frac{78}{12} = 78[/math]

(The area of four 3 foot by 78 inch doors)

Therefore the default door_area is 78 square feet.