What’s an ‘Egress’ Window—And Why Is It Important?

If you’ve ever looked into replacing your home’s windows, you might have heard the name egress window. Unlike generic terms like double-pane or single-hung, egress window doesn’t come up as often. You might nod wordlessly as a window salesperson makes the reference, then quickly change the subject.

1. The Egress Window, Explained
2. Egress Window Requirements
3. Egress Window Laws

You're not alone: Many people lack knowledge of what egress actually means. But there’s a really simple explanation, and it’s one that has the potential to save your life in an emergency. And no, that’s not hyperbole.

The Egress Window, Explained

The key difference between your standard residential window and an egress window is that the latter doubles as an exit out of the premises. (Per Merriam-Webster, the word egress means “a place or means of going out” or “the action or right of going or coming out.”) Its operation and dimensions permit occupants to make a safe and rapid evacuation, as in the case of a fire, when conventional entryways are unavailable or unsafe to approach.

Egress windows are most often found in finished basements, where occupants would have to ascend a flight of stairs in order to leave the home. Without a viable means of escape, a fire on the first floor could mean being trapped. With an egress window, people can flee without having to run toward danger. (An egress can also serve as a way in for first responders like firefighters.)

An egress window becomes even more of a priority when a basement contains bedrooms. The risk of sleeping through a spreading fire makes an avenue of escape mandatory in most residential building codes. (More on that in a bit.) But even if there is no basement bedroom, an egress window is still typically required if the basement is intended as a living space.

Because basements are partially below grade, or under the ground, an egress window is often installed near a window well, which provides space to maneuver once a person has exited through the window. If it’s low enough, some wells might come equipped with ladders or stairs to return to graded soil.

Safety isn’t the lone reason for an egress window—just the lone mandated reason. Egress windows can also provide additional natural light into a space, increase ventilation, and potentially increase the appeal of real estate for prospective buyers by meeting local building mandates.

Speaking of building codes ...

Egress Window Requirements

Because egress windows serve a very specific function, they’re usually subject to requirements. While this varies from region to region or city to city, the International Residential Code (IRC) that offers minimum building standards for residential properties provides some broad guidance. In general terms, the windows need to be large enough to permit human passage. In the state of Minnesota, for example, the fire code states egress exits need to be a minimum of 4.5 square feet. In Westbrook, Maine, the minimum is 5.7 square feet. These dimensions refer to the opening of the window, not its overall measurement. It’s the available space you can crawl through should you ever need to.

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There’s also typically a rule about how far the bottom of the egress window can be from the floor. Often, it’s a maximum of 44 inches.

Egress windows don’t have to open in any particular way. Some are casement windows, which swing on a hinge in a manner similar to a door and may operate by hand crank. Others are horizontal sliding windows with glass panes that essentially overlap each other when opened, meaning the overall dimensions of the window would need to be doubled to meet the minimum exit size. And some operate like conventional vertical sash windows that move up and down.

Because egress windows need to be operational quickly, they shouldn’t require a key or other apparatus to open. Nor should they be blocked by security bars or anything outdoors that would limit the window’s ability to fully open.

Egress Window Laws

It’s difficult to summarize egress window requirements, as they can vary considerably. But some cities or states make allowances for older buildings. In Minnesota, egress windows are not required if the property was constructed prior to July 1, 1972. Properties that are covered by fire sprinkler systems may also be exempt from egress regulations.

Many cities, including Portland, Oregon [PDF], require that all bedrooms have at least one egress window each regardless of which floor they’re on—unless the windows were original to the home at a time when bedrooms met previous code standards. Put another way: Your older home isn’t likely to be in violation of egress standards with your old bedroom windows, but you might want to consider installing one in each room for your own sake. As with a basement, the objective is to be able to leave a home even if the stairs are not usable. You’ll have to deal with a fall from a second or third floor, but it’s likely preferable to the alternative.

It's also possible your existing bedroom windows could double as egress windows, provided they offer an opening suitable for exit. That usually means a minimum width of 20 inches and a minimum height of 24 inches, though you can’t have the minimum for each and still reach the 5.7 square foot requirement. To do that, your 20-inch-wide window would need to be at least 42 inches tall.

Some areas may also relax egress standards if the bedroom has a door leading to another area of the home, as virtually all bedrooms do.

Equally as important as having an egress window is making sure it’s operational. Some home inspectors have found egress windows that have been painted shut or screwed closed, which would slow or hinder efforts to get through them in a hurry. Making sure the egress isn’t blocked off by furniture or otherwise non-functional is critical. So is making sure you don’t inadvertently replace a working egress window with a narrower one during remodeling.

What happens if you don’t have an egress window where one is required? In a basement, it might mean not having a bedroom legally recognized as a bedroom, which can be a problem when it comes time to sell the property. For main living floors, you’re unlikely to encounter any code or inspection problems if the home meets regional thresholds for being old enough to be exempt from modern building codes. (If you add or remodel a room on a property, however, then you’re likely to have to adhere to contemporary building standards.) When in doubt, you can always check your local building or fire codes and look for egress or “emergency escape and rescue opening,” or EERO, for further guidance.

Regardless of whether local codes demand it, it’s always best to have viable exits planned out in the event you need to make a quick escape from a building—especially if you’re in a basement. And if you’re shopping for a new home, it’s wise to keep an eye out to see what egress windows are on the premises. Like a lot of safety measures, it's better to have them and not need them than the other way around.

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