An egress window conforms to specific building code criteria so it can be used as an emergency exit by emergency personnel and the building's inhabitants. Not only does the window itself have to meet certain requirements, so does the window well. Therefore, if the window in the window well is going to be an egress window, you have specific requirements to consider to know whether or not you need to install a new or modify your window well.
Locate the two outer edges of your window well found on either side of the window. Measure the distance between the two. This is the length of the window well. If the window must meet egress requirements, the window well should be at least 36 inches long.
The width or projection of the window well is the measurement taken to determine how far out the window well protrudes from the window. It is typically at least 22 inches. However, to meet egress requirements, it must protrude at least 36 inches out from the window. Also, the total area of the window well should be a minimum of 9 feet. This measurement is taken by multiplying the width and length together.
The height or depth of the window well is measured from the bottom of the window well to ground level. If this height exceeds 44 inches and the window must meet egress requirements, a 12-inch wide ladder or steps must also be installed. However, the steps or ladder should remain at least 30 inches from the window -- and they shouldn't block the window from fully opening.