There’s no doubt that windows add incredible value to your home. They are a source of natural light, can assist with air circulation on a breezy day, and in energy-efficient models can actually save you some substantial costs on your utility bills. According to some building codes however, windows can (and must) serve as a lifesaver in providing an exit point in the case of an emergency.
Windows that are large enough for exiting and entering in emergency purposes are known as egress windows. These types of windows not only have to be large enough for escape and entry, they must also have a clearance built in around them. The codes that define egress windows are determined by three factors:
- Type of room
- Size of window
- Style of window
Type of Rooms Needing an Egress Window
The most obvious choice of where an egress window would need to be placed is in a bedroom. In the unfortunate event of a fire in the middle of the night, rescue crews must be able to access a bedroom no matter what story of the house it may lie. If a fire is present in a hallway and other interior areas of a home, residents must be able to escape to the outside safely via an egress window.
Egress windows also need to be installed if a basement is going to be finished into a habitable area, especially if an extra bedroom is going to be framed in. You definitely don’t want to be trapped underground in an emergency situation. Egress windows in a basement must also have an appropriate well built around them so that access to and from the basement can be granted. Wells need to project out a minimum of 36” and have a horizontal area of 44” wide. If the vertical depth into the basement well is greater than 44”, a ladder or steps must also be affixed permanently.
Egress Window Size Requirements
In order to satisfy egress window requirements, the unit must be able to be safely evacuated or entered by people of multiple body types. These window types must meet:
- have a minimum width opening of 20”
- have a minimum height opening of 24”
- have a minimum opening area of 5.7 ft2
- have a maximum sill height above the floor of 44”
Width opening and height opening are relatively self-explanatory. The minimum opening area (net clear opening) refers to the total space that is free and clear. It is based on a firefighter trying to enter through the window with his or her breathing apparatus in tow. Just because a window itself is a certain size doesn’t necessarily mean that the entire area is accessible, especially on double hung or awning style windows.
Sill height maximums are put in place so that the average person can enter into the window for escape without the use of a ladder. This mea
surement is taken from the inside of the home since second story egress windows are much higher than 44” from the ground.
If the escape window opening is between 44 inches and 52 inches off the finished floor height then securing a step, platform, or bed to the wall directly underneath the opening can be utilized. The top of the step, platform or bed shall be no more than 44 inches from the opening and should not protrude less than 18” from the wall.
Types of Windows that Can Be Used for Egress Purposes
Homeowners do not need to sacrifice their preferred aesthetics just to satisfy egress building code requirements. This is because a number of different window styles can be used as an egress so long as they provide an adequate opening for safe entry and exit. The pros and cons of specific window types include:
- Casement windows – take up the smallest amount of space while still fulfilling egress requirements. They are side hinged which provides the most net clear opening space of any window type. Casement windows can also be outfitted with an operator arm that allows the unit to open even further than standard.
- Double hung windows – a tricky option because even when the window is fully open, it slides vertically so that half of the opening is covered by glass and paneling. In order to fulfill egress requirements a double hung window needs to be over 4’9” in height. For most basements, there simply isn’t room for double hung windows.
- Sliding Windows – instead of opening vertically like a double hung window, these gliding windows slide horizontally which provides more opportunity to satisfy egress requirements.
There really aren’t many other window types that can meet egress codes. Awning windows are nowhere near large enough for access in and out and picture windows don’t open at all.
Does Your Windows Meet Egress Requirements?
It should also be noted that many older homes had different safety provisions considering means of egress. This doesn’t mean it wouldn’t be a safe option to replace them however. New home construction will need egress windows in all bedrooms and finished basements to meet inspection protocol. When you are replacing windows, a good rule of thumb to follow is to meet the egress minimums even though your local codes may not require it.
For escape windows installed prior to July 10, 2007:
- Minimum 20” width
- Minimum 20” height
- Minimum 4.5 square feet of clear opening
See the below link that provides dimensions and ways to measure current and past egress requirements: