If you add a bedroom in an unfinished basement or create a habitable space in your basement, an egress window must be installed in the bedroom.According to the International Residential Code (IRC) 2003 lower level egress requirements, egress windows and wells are required under the following circumstances:

• If you add a bedroom in an unfinished basement, an egress window must be installed in the bedroom.
• If you create a habitable space in your basement other than a bedroom and you currently do not have an egress window, one must be included with the installation of the habitable room.

And the dimensions of egress windows must comply with International Residential Code (IRC) requirements and local building codes.

Egress windows needs to meet the following specifications:

• Window opening must  provide at least nine square feet of space.
• Must be at least 36 inches long and wide.
• Must be equipped with a ladder if the well is deeper than 44 inches below grade.
• The ladder must be at least 12 inches wide. It can’t encroach more than six inches into the well but needs to be at least three inches away from the back wall. And the distance between the step rungs can’t exceed 18 inches.
• Because basement windows are a way out, they must open from the inside. Any screens, grilles or bars need to be removed from the inside without keys or tools.
• It’s also vital that basement windows can completely open. The window sash shouldn’t obstruct the opening. This allows your family to quickly exit—or first responders to quickly enter.