An egress window is large enough for someone to escape through in an emergency. Building codes generally require one in every basement bedroom. Most local codes follow the International Residential Code: a minimum net opening of about 5.7 sq ft (5.0 sq ft at grade floor), at least 24" high and 20" wide, with a sill no more than 44" above the floor, but always check your local code.
Cost at a glance
| Cost | Source | |
|---|---|---|
| National average | $4,216 | This Old House, egress window cost (updated June 2026) |
| Typical range | $2,718-$5,878 | This Old House, egress window cost (updated June 2026) |
| Window well excavation & install | $3,000-$7,000 | This Old House, egress window cost (updated June 2026) |
| Enlarging an existing opening | from $150-$200 | This Old House, egress window cost (updated June 2026) |
| Permits | $100-$500 | This Old House, egress window cost (updated June 2026) |
What affects the price
- New opening vs enlarging: cutting concrete or block is the biggest cost driver.
- Excavation and window well: deeper basements need bigger wells, sometimes with steps or a ladder.
- Drainage: a well needs a drain or gravel base to avoid water problems.
- Permits and inspection are almost always required.
Ways to save
- Enlarge an existing basement window rather than cutting a new opening.
- Get a contractor who handles cutting, excavation and the window: fewer trades, fewer markups.
Get an accurate price
Online averages are a starting point. Window prices depend on exact sizes, your home’s condition and local labor rates, so the only reliable number is an itemized, in-home quote. Compare at least three, and use our window cost calculator to sanity-check them.
Frequently asked questions
Do I need an egress window in my basement?
If the basement has a sleeping room, codes generally require one emergency escape opening per bedroom. Unfinished basements may need one too if habitable space is added.
Does an egress window add value?
It can make a basement bedroom legal to list as a bedroom, which can affect appraisal and sale price.
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