Skip to Content

What Is The Minimum Opening For An Egress Window?

For most of us, our homes are the most loving and peaceful place on the planet where we spend time with our loved ones. And to guarantee their safety, we must install a huge egress window that can act as an emergency exit in case of danger. And this got me thinking, “what is the minimum opening for an egress window?” So after thorough research, this is what I discovered.

According to the IRC (the International Residential Code), all bedrooms and basements must have a rescue and emergency escape opening. The international building codes stipulate that these windows should have a height of about 24 inches and a width of approximately 20 inches. (2)

After all, the safety of the people living in our homes is our responsibility. So in this article, we’ll show you the minimum requirements for an egress window. We’ll also teach you how to determine the net clear opening of an egress window for both your bedrooms and basements.

What Is the Minimum Opening For an Egress Window?

The IRC stipulates that any bedroom in a hotel built after 1992, camping cabin, vacation home, and resort must have an exterior escape opening. (2) The opening could be a window in the bedroom and basement with a minimum opening area of about 5.7 square feet.

It means that:

  • It should have a minimum height of about 24 inches.
  • It should have a width of about 20 inches.
  • The top window sill height of the egress window should be at least 48 inches above the ground. However, some municipality codes can be very restrictive.
  • It must be possible for a person to open the window from the inside without using any separate key, effort, special knowledge, or tool. (3)

How Is the Net Clear Opening Of the Egress Window Determined? 

A net clear opening is the free and clear space created when you open your window. To get the net clear opening of an egress window, you measure its height and width when the window is opened fully.

Note: This post may contain affiliate links which will take you to online retailers that sell products and services. If you click on one and buy something, I may earn from qualifying purchases. See my Affiliate Disclosure for more details.

Take the measurements from the inside and only measure the part that is opened. Once you have the measurements, you can multiply the height times the width and then divide it by a square foot or 144 square inches. And if the results exceed 5.7 square feet, it meets the requirement and can serve as an egress window. (2)

A window that is barely 20 inches wide and 24 inches high doesn’t meet the needed requirements. And that is because the opening will be 3.33 square feet. And to meet the threshold, the window must be wider or taller than the minimums to create an opening of about 5.7 square feet. (2)

What Are the Requirements for a Basement Egress Window?

On top of that, the egress windows requirement for basement windows differs from those installed in bedrooms. The basement egress window should have a width and height of about 36 inches with a reliable opening. The basement windows should have a window well that can provide enough clearance. (5)

Basement egress windows provide several other challenges that they must meet. Other than the standard requirements, these windows must provide a floor area of about 9 square feet. And if the window well is over 44 inches high, you must install a ladder.

The ladder should be projected about 3 inches from the window well and be 12 inches wide. And if your home’s window well is built from timber, you can add some steps instead of adding a ladder.

If the window is situated under the porch or deck, the inspectors need the distance between the porch joists or the deck base and the window well to be about 36 inches. If the window’s base is over 44 inches from the floor, most jurisdictions will let you add some steps to reduce this height to 36 inches.

How to Select the Right Egress Window Size?

An egress window should be fitted to the right size in line with safety requirments

When planning to install an egress window in your home, you need to understand that bedroom windows vary in size and style. Some huge windows make greater egress windows than others. So while installing an egress in your home, you should pick something that matches the window’s styles and meets the IRC requirements.

Achieving this can be pretty challenging, so you should put the following pros and cons into consideration when selecting your new egress window:

1. Casement Window

Casement windows are unique side-hinged windows that take up less space. Therefore, they are ideal for places with limited space and basements. And to meet the requirements, some casement windows have specialized operator arms that allow them to open wider than standard windows.

Casement windows are great but make sure you leave a “push here” label on them. These windows are used in pairs or singly, and they are generally attached to their frames by hinges. (6) These windows have lower air leakage than other types of windows.

2. Double-Hung Windows

A double-hung window has two glass panes engineered for the bottom and top sashes to be lowered and raised. Therefore, even when opened, half the window is typically blocked by the glass. For a double-hung to be used as an egress, it must have a height of about 4 feet 9 inches.

This height makes it not ideal for most basements. This window is more efficient than the single-hung option, and it can help you lower your cooling and heating costs. (7) The fact that you can open both sides halfway means that the cooler air can get in through the lower part while the warm air can escape through the top part.

3. Awning Windows

Awning windows are top-hinged options that can make inferior basement egress windows. And that is because the opened sash can prevent folks from leaving or getting into the basement. Plus, the ones with central opening mechanisms don’t meet the requirements as the hardware blocks people from getting in and out of the basement.

Most old awning windows have limited opening space, so make sure you check if they are up to code. Luckily, the new options have a height of between 23.5 inches and 36 inches and are about 48 inches wide. (1)

4. Gliding Windows

For these to be used as egress windows, they must be about 4 feet high and 4 feet wide. And the good thing about gliding windows is that they allow more than enough light into the basement region. Like a double-hung window, gliding windows need more space than the casements to meet the codes. (3)

5. Single-Hung Windows

Single-hung is quite popular in places with cold weather and older houses. And since one sash is stationary, these windows need to be huge to be used as egress windows. (1)


If My Window Has a Net Opening Of 5.7 Square Feet, Will It Automatically Meet Egress?

Only windows that have exceeded the minimum dimensions are considered to be great options for egress. After all, a 5.7 feet high by a 1-foot wide window is too narrow for anyone to use. Therefore, it doesn’t pass the IRC code. (2)

Should Every Bedroom in my House have an Egress Window?

Technically, all bedrooms must have at least one form of egress, and this can be either a window or a door. And since most bedroom doors cannot be used as exits, they should have an egress window.

Does My Egress Window Well Need a Cover?

Even though it’s not mandatory, a cover can be pretty important if the emergency exit is near a playground or a walkway. However, the cover can block ventilation and sunlight. A window well cover can block the emergency exit, mainly when it’s covered by snow. (8)

Final Thoughts

Every building must have an emergency exit or entrance, which people can use to escape in case of fire, or the firefighters can use to get in and save people. Before you even walk into the store and purchase an egress window, you must determine the right size for your home and where it should be installed. Make sure you do your research and find out which type of egress window can fit your home, and if you have a small house, you should avoid windows that open halfway.