Egress Window Dimensions 🏠 Everything Homeowners Need to Know

Adding an egress window isn’t just about style—it’s about safety, code compliance, and boosting home value. If you’re finishing a basement or upgrading an older home, you’ve likely asked: what are the standard egress window dimensions?

“Egress windows are required by building code for any basement bedroom or habitable space to provide a safe emergency exit.”

This article covers egress window dimensions, code requirements, installation considerations, and the cost to install an egress window.

Why Egress Windows Matter

Egress windows serve two critical purposes:

1. Safety – They provide an escape route during emergencies such as fire.

2. Legal Compliance – Building codes in most regions require them in finished basements.

3. Added Value – A basement bedroom without an egress window doesn’t count as a legal bedroom in most real estate listings.

Standard Egress Window Dimensions

To qualify as a true egress window, dimensions must meet specific building code standards.

Requirement	Minimum Measurement
Net Clear Opening Area	5.7 sq. ft. (5.0 sq. ft. for ground floor)
Opening Height	At least 24 inches
Opening Width	At least 20 inches
Maximum Sill Height	44 inches from the floor
Window Well (if below grade)	9 sq. ft. minimum with 36 inches projection

These numbers are not just recommendations—they are required by the International Residential Code (IRC).

Window Types That Work for Egress

Not every window style qualifies. Some common types include:

• Casement windows – Great for small openings since the full sash swings out.

• Sliding windows – Must be large enough to meet opening area requirements.

• Double-hung windows – Rarely used, since the opening area can be too small.

• In-swing windows – Allowed but need to clear obstructions inside.

“Casement windows are often the most space-efficient option for basements, offering the widest clear opening.”

Cost to Install an Egress Window

So, how much does it cost to install an egress window?

Project Type	Average Cost (USD)
Adding to existing basement wall	$2,500 – $5,000
Converting existing window to egress	$1,500 – $3,500
Adding a window well & drainage	$2,000 – $6,000
DIY (not recommended)	$800 – $1,500

The cost to install an egress window varies depending on labor, excavation, and finishing work. For example, a basement wall cutout is far more expensive than converting an oversized existing window.

Installation Considerations

• Cutting into foundation walls – This requires professional tools and expertise.

• Window well drainage – Without proper drainage, you risk basement flooding.

• Flashing on windows – Proper flashing prevents water intrusion and long-term damage.

• Local codes – Always check regional rules, as some cities have stricter requirements.

DIY vs Professional Installation 🛠️

While handy homeowners may be tempted to DIY, egress window installation is typically a pro job.

Approach	Pros	Cons
DIY	Lower cost upfront	Risk of code violations, water leaks, structural damage
Professional	Guaranteed code compliance, warranty	Higher upfront cost

“Cutting into a basement wall without professional expertise can lead to structural failure and costly water damage.”

Long-Term Benefits of Installing an Egress Window

• Adds legal bedroom space – Boosts resale value.

• Increases natural light – Brightens dark basements.

• Improves ventilation – Better airflow reduces mold growth.

• Safety – Peace of mind for families.

Conclusion

So, what are the egress window dimensions? A true egress window must provide at least 5.7 sq. ft. of clear opening, be 20 inches wide, 24 inches tall, and no higher than 44 inches from the floor.

The cost to install an egress window generally ranges from $1,500 to $5,000 depending on complexity. While expensive, it’s a project that ensures safety, code compliance, and long-term property value.

FAQ

What are the standard egress window dimensions? Minimum 20" wide, 24" tall, with 5.7 sq. ft. clear opening and sill no higher than 44".

How much does it cost to install an egress window? Expect $1,500 to $5,000 depending on whether excavation or a window well is needed.

Can any window be used as an egress window? No, it must meet code requirements for width, height, and opening area.

Do basement bedrooms need an egress window? Yes, most building codes require it for safety and legality.

Is DIY installation possible? It is, but professional installation is recommended to avoid structural and drainage problems.