What Is An Egress Window?

An egress window is a common household window that is large enough for entry or exit in case of an emergency. These are typically required when finishing a basement and are paired with an attached ladder or steps for an easy escape route.

Attachments and included information is for general information only. Due to area and region specific building codes and requirements consult with your architect or builder.

Common Building-Code Violations: Emergency-Egress Windows Too Small

An undersized egress window in a bedroom can spell disaster in a fire

The one thing that inspectors never fail to check is the required emergency-egress window from a sleeping room. At least one window in each bedroom must be of sufficient size to permit the occupants to escape a fire and also to allow a fully outfitted firefighter to enter.

An egress window must satisfy all four Internatioinal Residential Code (IRC) criteria:

  • Minimum width of opening: 20 in.
  • Minimum height of opening: 24 in.
  • Minimum net clear opening: 5.7 sq. ft. (5.0 sq. ft. for ground floor).
  • Maximum sill height above floor: 44 in.

Do the math

At first glance, you might assume that a 20-in. by 24-in. window (A) would be acceptable for egress. Those dimensions would yield a net clear opening of only 3.3 sq. ft.

To achieve the required net clear opening of 5.7 sq. ft., a 20-in. wide window (B) would have to be 42 in. high.

Likewise, a 24-in. high window (C) would have to be 35 in. wide.