What does basement window replacement cost?
Standard basement window (hopper style) replacement runs $250 – $800 installed. Glass block runs $400 – $900. An egress window — required for any basement bedroom — costs $2,500 – $5,500 installed including the well and excavation.
The egress window cost jump is real because it requires cutting the foundation wall and digging a window well — not just swapping a frame. If a basement room is being used as a bedroom without an egress window, that's a code violation and a safety issue.
Basement window types and costs
| Window type | Best for | Code note | Installed cost |
|---|---|---|---|
| Hopper window | Best for: Standard basement utility areas, laundry rooms, mechanical rooms — opens inward from the top. Most common basement window type | Direct frame swap in most cases — same rough opening. Vinyl frames are low-maintenance and resist the moisture typical in basements | $250 – $800 installed |
| Sliding or single-hung basement window | Best for: Wider basement openings, semi-finished basements where more light is desired | Direct replacement if rough opening matches; may require minor framing adjustment for size change | $350 – $900 installed |
| Glass block window | Best for: Security-focused installations (glass block is nearly impossible to break through); utility areas where light but not ventilation is needed | Installed as a mortar-set block system or prefabricated panel — not a standard sash replacement. Requires masonry or glass block specialist | $400 – $900 installed per opening |
| Egress window (new opening) | Best for: Basement bedrooms or legal sleeping areas — required by building code (IRC requires minimum 5.7 sq ft opening, 24 in. height, 20 in. width, max 44 in. sill height from floor) | Requires cutting foundation wall, excavating a window well, waterproofing the well, and installing a full egress-compliant window. Permit required | $2,500 – $5,500 installed including excavation and well |
| Egress window well upgrade (existing egress) | Best for: Replacing a damaged or undersized window well on an existing egress opening; adding a well cover to keep water out | Steel or composite prefab well; cover installation. Does not involve foundation cutting | $500 – $1,500 installed |
Try this first (before you pay anyone)
- If you have a basement room being used as a bedroom, confirm it has an egress window — if not, that's a safety and code issue that needs to be addressed, not ignored.
- Measure your existing window rough opening (width × height of the hole in the foundation) before calling for quotes — contractors can give faster estimates when they know if it's a standard size.
- Check for water infiltration around the frame: if the concrete block around the window is stained, efflorescent (white powder deposits), or crumbling, the window well drainage may need to be fixed at the same time.
- For basement bedrooms, verify the egress window meets minimum opening requirements yourself — the sill height from the floor should be 44 inches or less, and the opening itself at least 20 × 24 inches.
Call a pro when…
- You're finishing a basement and adding a sleeping room — you need an egress window before that room can legally be used as a bedroom
- The existing window frame is rotted, leaking, or the glass is broken and exposing the basement to weather or pests
- You want glass block installed — this requires masonry skill; it's not a DIY-friendly swap
- Water is coming in around the window frame — the window well drainage or exterior waterproofing may need attention alongside the window
Repair or replace?
A standard basement hopper window with a cracked pane or worn weatherstrip can often be repaired for under $200. Replace when the frame is rotted or corroded (aluminum frames in wet basements corrode badly), when the window no longer seals or operates properly, or when you're upgrading a bedroom space that needs egress. Don't skip the egress requirement — a non-egress basement bedroom is a real fire-safety risk and will fail a home inspection at resale.
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Related questions
Does a basement bedroom legally require an egress window?
Yes. The International Residential Code (IRC) requires any room used for sleeping to have an egress window (or door) that meets minimum size requirements: 5.7 sq ft net opening, minimum 24 inches in height, minimum 20 inches in width, and a sill no higher than 44 inches from the floor. Most municipalities have adopted IRC — check your local code to confirm.
How long does basement window replacement take?
A standard hopper or sliding window swap takes 1–2 hours per window. Glass block installation takes a half day per opening due to mortar setting time. An egress window with excavation and well installation is a full-day job, sometimes two days.
Can I replace my own basement windows?
A standard hopper or vinyl window in an existing rough opening is a manageable DIY for someone comfortable with basic carpentry and caulking. Glass block and egress windows are not DIY-friendly — glass block requires masonry skills, and egress installation involves cutting concrete foundation which requires permits and specialized equipment.
What size is a standard basement window?
The most common basement hopper window rough openings are 32 × 16 inches and 32 × 24 inches, but older homes vary widely. Measure your opening before ordering or getting quotes — non-standard sizes may require a custom unit or framing adjustment.