What is an Egress Window?

A basement Egress Window is a window that has 5.7 square feet of clear net internal opening allowing an occupant to easily escape a fire or a fully outfitted fireman to enter the area from outside to rescue a person or fight the fire.

The current International Residential Code (IRC) defining what is needed requires all finished basements and basement bedrooms, to have two ways out. The first being the normal basement steps to the first floor, and the second being an emergency-egress window or door to the outside, permitting occupants two ways to escape and firemen two ways to enter during a fire emergency.

If an Egress Window is used to exit a basement bedroom then it must be installed in that bedroom. If there are two or more bedrooms in the basement each one must have its own egress escape window.

What are the International Residential Egress Window Code (IRC) requirements used by all municipalities in the USA? 

What are the International Residential Egress Window Code (IRC) requirements used by all municipalities in the USA? 

  • Minimum required width of clear opening: 20 inches
  • Minimum required height of clear opening: 24 inches
  • Minimum net clear opening: 5.7 sq. ft. (5.0 sq. ft. for ground floor Windows)
  • Maximum allowable window sill height above floor: 44 inches – Target a sill height of 42 inches to allow room for errorLet’s do the math:
  • 20 inch wide x 24 inch high clear opening is only 3.3 sq. ft. not 5.7 sq. ft. as code requires
  • But a 20 inch wide x 41 1?4 inch high clear opening equals the 5.7 sq. ft. required by code.
  • Or a 34 1?4 inch wide x 24 inch high clear opening also equals 5.7 sq. ft.

What are the types of Egress Windows?

Single Hung In-swing Window:

Pro’s – Built with egress hinges this dual function in-swing egress window maximizes the clear egress opening by allowing both the top and bottom sashes to be used in determining the net 5.7 sq. ft. clear opening of this window. An in-swing window also eliminates issues with cover interference when part of a window sticks above the top of the egress well. These windows also work well in small compact wells;
Con’s – Slightly more expensive Casement In-swing Window:

Pro’s – Built with egress hinges, this is the smallest in-swing egress window available that meets 5.7 sq. ft. IRC code requirement. Since it in-swings into the room it works well in small compact wells, and causes no issue with well cover interference if the window sits partially above the top of the Egress Well.
Con’s – Slightly more expensive Standard Double Hung Window:

Pro’s – Many inexpensive Windows are available;
Con’s – Windows need to be very large to meet the egress code because of only being able to utilize the lower half of the window to meet the 5.7 sq. ft. clear area code requirement for escape.

Casement Outswing Window:

Pro’s – Many inexpensive Windows are available.
Con’s – Usually not made with egress hinges, many don’t open 90 degrees, requires the use of

wider widows and wells, will interfere with well cover when the top of the window is partially above the top of the egress well.

Standard 48” Sliding Basement Window:

Pro’s – Many inexpensive 3 1?4” jamb depth Windows are available.
Con’s – Only specialized egress sliding windows meet the IRC 20” minimum wide right to left clear opening requirement of the egress code.

Egress 48” Sliding Basement Window:

Pro’s – Designed to meets the Egress Code 20” clear width opening requirement.
Con’s – Could be more expensive.

How do I measure an egress windows net clear opening?

How do I measure an egress windows net clear opening?