What is an egress window?

What is the purpose of an egress window?

Its purpose is life safety: the code definition gives it two jobs, a means of escape for the people inside the room and access for rescue from outside, and the opening must lead outdoors to a public way, or to a yard or court that opens to one. The City of Dubuque, Iowa building department and the Ohio code put it like this: “Emergency escape and rescue openings are an essential aspect of life safety.” Source: City of Dubuque, Iowa, Inspection & Construction Services Department, read 2026-10-29. In Ohio, “Emergency escape and rescue openings shall open directly into a public way, or to a yard or court that opens to a public way.” Source: Ohio Board of Building Standards (Ohio Administrative Code), read 2026-10-29.

How do residential codes define an egress window?

An egress window is a window that works as an emergency way out of a room: it opens wide enough, sits low enough and works from inside without a key, so a person can climb out and a rescuer can climb in. Residential codes call it an emergency escape and rescue opening, and a door can fill the same role. The Residential Code of Ohio defines it this way: In Ohio, “An operable exterior window, door or similar device that provides for a means of escape and access for rescue in the event of an emergency.” Source: Ohio Board of Building Standards (Ohio Administrative Code), read 2026-10-29. “They are required in basements, habitable attics, and at least (1) must be found in every sleeping room.” Source: City of Dubuque, Iowa, Inspection & Construction Services Department, read 2026-10-29. In Ohio, “Where a door is provided as the required emergency escape and rescue opening, it shall be a side-hinged door or a slider.” Source: Ohio Board of Building Standards (Ohio Administrative Code), read 2026-10-29.

What is the minimum size of an egress window?

The size rule is about the clear opening when the sash is open, not the glass or the frame: at least 5.7 square feet, at least 24 inches high and at least 20 inches wide, with 5 square feet allowed for a grade floor opening (a sill within 44 inches of the ground outside). Meeting only the minimum height and the minimum width gives 480 square inches, short of the roughly 821 that 5.7 square feet needs, so one side must be larger. The Residential Code of Ohio sets these figures: In Ohio, “Emergency and escape rescue openings shall have a net clear opening of not less than 5.7 square feet (0.530 m2).” Source: Ohio Board of Building Standards (Ohio Administrative Code), read 2026-10-29. In Ohio, “The net clear height of the opening shall be not less than 24 inches (610 mm) and the net clear width shall be not less than 20 inches (508 mm).” Source: Ohio Board of Building Standards (Ohio Administrative Code), read 2026-10-29. In Ohio, “Grade floor openings or below-grade openings shall have a net clear opening area of not less than 5 square feet (0.465 m2).” Source: Ohio Board of Building Standards (Ohio Administrative Code), read 2026-10-29. In Ohio, “A window or other opening located such that the sill height of the opening is not more than 44 inches (1118 mm) above or below the finished ground level adjacent to the opening.” Source: Ohio Board of Building Standards (Ohio Administrative Code), read 2026-10-29.

Does a bedroom need an egress window?

Yes: the Ohio, Minnesota and Oregon codes quoted on this page require at least one operable emergency escape and rescue opening in every sleeping room, and Ohio applies the same rule to each new sleeping room in an addition. The opening can be a window or a qualifying door. The Ohio and Minnesota rules read: In Ohio, “Every sleeping room shall have not less than one operable emergency escape and rescue opening.” Source: Ohio Board of Building Standards (Ohio Administrative Code), read 2026-10-29. In Ohio, “Where dwelling additions contain sleeping rooms, an emergency escape and rescue opening shall be provided in each new sleeping room.” Source: Ohio Board of Building Standards (Ohio Administrative Code), read 2026-10-29. In Minnesota, “Basements, habitable attics, and every sleeping room shall have not less than one operable emergency escape and rescue opening.” Source: Minnesota Office of the Revisor of Statutes, read 2026-10-29.

Does a basement need an egress window?

It depends on the room and the state. Minnesota and Oregon require an opening in the basement itself and one in each basement bedroom, Ohio exempts some sprinklered basement bedrooms, and alterations to an existing basement do not trigger the rule unless a new bedroom is created. The rules read: In Minnesota, “Where basements contain one or more sleeping rooms, an emergency egress and rescue opening shall be required in each sleeping room, but not be required in adjoining areas of the basement.” Source: Minnesota Office of the Revisor of Statutes, read 2026-10-29. In Ohio, “An emergency escape and rescue opening is not required where existing basements undergo alterations or repairs.” Source: Ohio Board of Building Standards (Ohio Administrative Code), read 2026-10-29. In Minnesota, “New sleeping rooms created in an existing basement shall be provided with emergency escape and rescue openings in accordance with Section R310.1.” Source: Minnesota Office of the Revisor of Statutes, read 2026-10-29. In Ohio, “Where the dwelling or dwelling unit is equipped with an automatic sprinkler system installed in accordance with Section 2904, sleeping rooms in basements shall not be required to have emergency escape and rescue openings provided that the basement has one of the following:” Source: Ohio Board of Building Standards (Ohio Administrative Code), read 2026-10-29. In Oregon, “Basements and every sleeping room must have at least one operable emergency escape and rescue opening.” Source: City of Portland, Oregon, Permitting & Development, read 2026-10-29.

How high off the floor should an egress window be?

No higher than 44 inches: the codes measure from the finished floor inside the room to the bottom of the clear opening, and a sill set below the ground outside then needs a window well. The Ohio code, the Jersey County, Illinois handout on IRC R310 and the City of Portland, Oregon page say: In Ohio, “Where a window is provided as the emergency escape and rescue opening, it shall have a sill height of not more than 44 inches (1118 mm) above the floor; where the sill height is below grade, it shall be provided with a window well in accordance with Section 310.2.3.” Source: Ohio Board of Building Standards (Ohio Administrative Code), read 2026-10-29. “Sill height: the sill height shall not be more than 44 inches above the floor.” Source: Jersey County, Illinois, Code Administration, read 2026-10-29. In Oregon, “Where emergency escape and rescue openings are provided they shall have a clear opening of not more than 44 inches above the floor.” Source: City of Portland, Oregon, Permitting & Development, read 2026-10-29.

What is an egress window well?

An egress window well is the open area dug outside a basement egress window whose sill sits below the ground, sized so the window can open fully and a person can climb up and out. Ohio sets 9 square feet of floor area, 36 inches of projection and width, and a fixed ladder or steps once the well is deeper than 44 inches. The rules read: In Ohio, “The horizontal area of the window well shall be not less than 9 square feet (0.9 m2), with a horizontal projection and width of not less than 36 inches (914 mm).” Source: Ohio Board of Building Standards (Ohio Administrative Code), read 2026-10-29. In Ohio, “The area of the window well shall allow the emergency escape and rescue opening to be fully opened.” Source: Ohio Board of Building Standards (Ohio Administrative Code), read 2026-10-29. In Ohio, “Window wells with a vertical depth greater than 44 inches (1118 mm) shall be equipped with a permanently affixed ladder or steps usable with the window in the fully open position.” Source: Ohio Board of Building Standards (Ohio Administrative Code), read 2026-10-29. In Ohio, “Ladders or rungs shall have an inside width of not less than 12 inches (305 mm), shall project not less than 3 inches (76 mm) from the wall and shall be spaced not more than 18 inches (457 mm) on center vertically for the full height of the window well.” Source: Ohio Board of Building Standards (Ohio Administrative Code), read 2026-10-29. In Oregon, “Emergency escape and rescue openings with a finished sill height below the adjacent ground elevation shall be provided with a window well in accordance with Oregon Residential Specialty Code section R310.2.3.” Source: City of Portland, Oregon, Permitting & Development, read 2026-10-29.

Can an egress window be under a deck?

Yes, under the Ohio rule, provided the window still opens fully and a clear path at least 36 inches high leads from it out to a yard or court, so a person can crawl out from under the deck. The Ohio code and the City of Portland, Oregon page say: In Ohio, “Emergency escape and rescue openings installed under decks and porches shall be fully openable and provide a path not less than 36 inches (914 mm) in height to a yard or court.” Source: Ohio Board of Building Standards (Ohio Administrative Code), read 2026-10-29. The City of Portland, Oregon, Permitting & Development source uses the same words as the passage quoted above.

What makes a window an egress window?

Size alone does not make it one: the full clear opening has to be reached by the window's normal operation from inside, with no keys, tools or special knowledge, and any device that limits how far the window opens has to meet the ASTM F2090 standard. The Residential Code of Ohio says: In Ohio, “Emergency escape and rescue openings shall be operational from the inside of the room without the use of keys, tools or special knowledge.” Source: Ohio Board of Building Standards (Ohio Administrative Code), read 2026-10-29. In Ohio, “Window opening control devices on windows serving as a required emergency escape and rescue opening shall comply with ASTM F2090.” Source: Ohio Board of Building Standards (Ohio Administrative Code), read 2026-10-29. In Ohio, “The net clear opening dimensions required by this section shall be obtained by the normal operation of the emergency escape and rescue opening from the inside.” Source: Ohio Board of Building Standards (Ohio Administrative Code), read 2026-10-29.

What is an egress window cover?

An egress window cover is a lid, grate or similar device placed over the window or its window well, and the Ohio code treats it like bars and grilles: it may not shrink the required opening or well, and someone inside must be able to release or remove it with no key, tool or special knowledge and no more force than opening the window takes. Section 310.4 of the Residential Code of Ohio says: In Ohio, “Where bars, grilles, covers, screens or similar devices are placed over emergency escape and rescue openings, area wells, or window wells, the minimum net clear opening size shall comply with Sections 310.2.1 through 310.2.3, and such devices shall be releasable or removable from the inside without the use of a key, tool, special knowledge or force greater than that required for the normal operation of the escape and rescue opening.” Source: Ohio Board of Building Standards (Ohio Administrative Code), read 2026-10-29.

Sources

• Residential Code of Ohio, rule 4101:8-2-01 Definitions — Ohio Board of Building Standards (Ohio Administrative Code); published 2019-07-01; read 2026-10-29.
• Residential Code of Ohio, rule 4101:8-3-01 Building planning, Section 310 Emergency escape and rescue openings — Ohio Board of Building Standards (Ohio Administrative Code); published 2019-07-01; read 2026-10-29.
• Minnesota Rules 1309.0310, Section R310 Emergency escape and rescue openings — Minnesota Office of the Revisor of Statutes; published 2020-03-31; read 2026-10-29.
• Emergency Escape and Rescue Openings (Oregon Residential Specialty Code R310) — City of Portland, Oregon, Permitting & Development; read 2026-10-29.
• Building Handout: International Residential Code (IRC) R310 Emergency Escape and Rescue Openings — Jersey County, Illinois, Code Administration; read 2026-10-29.
• Emergency Escape & Rescue Openings — City of Dubuque, Iowa, Inspection & Construction Services Department; read 2026-10-29.