Basement windows are small windows set in or just above the foundation wall, most often hoppers or sliders about 30 to 32 inches wide and 12 to 24 inches tall. Replacing one typically costs $400 to $1,000 installed. Adding a code-size egress window with a well is a bigger job at $2,723 to $5,898, averaging $4,244.
Prices updated September 2026.
This is a neutral buyer’s guide to basement windows: the main types, standard sizes, the egress rules that decide what you are allowed to install, and what replacement really costs once you add a window well. Prices are US figures from 2025 and 2026 sources, listed at the end.
What makes basement windows different
A basement window lives a tougher life than the ones upstairs. It sits in concrete or block, often at or below the soil line, and deals with splashback, snow and damp air. The parts you will hear about in quotes:
- Rough opening and buck: the hole in the foundation, usually lined with a wood or vinyl frame (the buck) that the window fastens to.
- Frame and sash: the window itself, most often vinyl as the cost-effective pick.
- Window well: a steel, plastic or concrete liner that holds soil back from a window set below grade.
- Well cover and drain: keep rain, leaves and animals out and let water escape.
Types of basement windows
| Type | How it opens | Can it be egress? | Unit price (prefab) | Best for |
|---|---|---|---|---|
| Hopper | Hinged at the bottom, tilts in from the top | No, too small | $100–$300 | Storage, laundry, utility rooms |
| Awning | Hinged at the top, swings out | No, too small | $100–$600 | Airflow during light rain |
| Slider | Sashes glide sideways | Yes, in larger sizes | $250–$625 | Finished rooms and egress |
| Casement | Side-hinged, cranks out | Yes, wide clear opening | $100–$750 | Egress where the well has swing room |
| Glass block | Fixed | No | $100–$400 | Privacy and security |
| Egress window | Any style sized to meet code | Yes, by definition | $100–$750 | Basement bedrooms and living space |
Pros and cons of the three most common picks
- Hopper: cheap, compact, secure, easy to clean from inside and good for ventilation. But it cannot serve as an escape route.
- Slider: wide opening, no swing space needed in the well, and a common egress choice. It costs more than a hopper, and only half the sash opens.
- Glass block: private, secure and moisture resistant with almost no upkeep. It lets in light but no fresh air and can never count as egress.
Standard basement window sizes (chart)
Angi lists 31¾ x 15¾ inches as the standard hopper size, with most units 30 to 36 inches wide and 12 to 24 inches tall. We added each size’s frame area. That number matters later: even the largest common hopper frame is smaller than the 5.7 sq ft clear opening an egress window needs.
| Width x height (inches) | Frame area | Big enough for egress? |
|---|---|---|
| 30¾ x 12¾ | 2.72 sq ft | No |
| 30¾ x 14¾ | 3.15 sq ft | No |
| 30¾ x 18¾ | 4.00 sq ft | No |
| 31¾ x 15¾ (most common) | 3.47 sq ft | No |
| 31¾ x 17¾ | 3.91 sq ft | No |
| 31¾ x 21¾ | 4.80 sq ft | No |
| 31¾ x 23¾ | 5.24 sq ft | No |
| Egress-size units: 24 x 36 up to 48 x 48 | 6 to 16 sq ft | Can be, if the clear opening meets code |
Measuring for a replacement: measure the opening’s width at the top, middle and bottom, and the height at the left, center and right. Use the smallest of each. Basement openings are often out of square, and a custom size can cost more than prefab: Angi puts custom units at $150 to $1,200 vs $100 to $800 for prefab.
Egress requirements (short summary)
Under the International Residential Code (IRC R310), basements and every sleeping room need at least one operable emergency escape opening, with limited exceptions such as a small basement used only for mechanical equipment. If a basement has several bedrooms, each one needs its own. The key numbers:
- Net clear opening of at least 5.7 sq ft (5.0 sq ft for grade-floor openings)
- At least 24 inches of clear height and 20 inches of clear width
- Sill no higher than 44 inches above the finished floor
- Window well at least 9 sq ft, projecting at least 36 inches from the wall and 36 inches wide, with a permanent ladder if it is deeper than 44 inches
Note that the minimums do not multiply out: 20 x 24 inches is only 3.33 sq ft. A 24-inch-wide opening needs about 34.2 inches of clear height (820.8 sq in ÷ 24) to reach 5.7 sq ft. Swapping a window in an existing opening does not always trigger these rules, but finishing a basement or adding a bedroom usually does. Cities adopt different code editions and local amendments, so check with your building department before you order. A full egress install averages $4,244, with most jobs between $2,723 and $5,898.
Materials: vinyl vs aluminum vs glass block
| Material | Unit price (prefab) | Strengths | Watch-outs |
|---|---|---|---|
| Vinyl | $100–$650 | Won’t rot or need paint; widest size selection | Fewer color options than wood |
| Aluminum | $300–$675 | Strong, slim frames | Metal conducts cold, so it can sweat in damp basements |
| Glass block | $100–$400 | Privacy, security, moisture resistance | Fixed, so no airflow and no egress |
| Fiberglass | $250–$800 | Durable and strong | Higher price |
| Wood | $175–$800 | Matches older trim | Needs upkeep near damp soil |
| Steel | $275–$800 | Security | Can rust if the finish is damaged |
Basement window replacement cost (per window + window well)
Most online guides stop at the window. In a basement, the well and any foundation cutting often cost more than the glass. Here is the full picture.
| Item | Typical cost | Source |
|---|---|---|
| Replace a standard basement window, installed | $400–$1,000 per window | Angi, Aug 2026 |
| Basic install of an in-stock unit | $549–$790 per window | Homewyse, Sept 2026 |
| Labor only | $100–$300; complex jobs up to $600 | Angi, Aug 2026 |
| New well, metal / plastic / concrete (egress job) | $200–$600 / $250–$800 / $750–$2,500 | Angi egress guide, Aug 2026 |
| Remove and replace an existing well | $1,000–$5,000 total | HomeGuide, Feb 2026 |
| Well cover | $50–$500 (Angi); $250–$500+ (HomeGuide) | Angi / HomeGuide |
| Egress window, fully installed | $2,723–$5,898 (average $4,244) | Angi, 760 projects, Aug 2026 |
Why do the window well numbers disagree? Angi’s are component prices inside a new egress install, where the crew is already digging. HomeGuide’s $1,000 to $5,000 covers tearing out an old well and setting a new one, including $400 to $1,400+ of labor. Homewyse’s range also leaves out framing repair, permits and 13% to 22% contractor overhead.
Basement window jobs: typical price per window
Basic install of an in-stock unit: $549 to $790
Replace a standard basement window: $400 to $1,000
Replace an existing window well: $1,000 to $5,000
Add an egress window (cut, well, window): $2,723 to $5,898
Scale: $0 to $6,000. Sources: Angi basement window guide (Aug 2026) and egress guide (Aug 2026, 760 projects); Homewyse (Sept 2026); HomeGuide window well guide (Feb 2026).
Worked example: you are finishing a basement with 4 old hopper windows and one new bedroom. Replace the 4 hoppers at $700 each (midpoint of Angi’s $400–$1,000) = $2,800. Add one egress window for the bedroom at Angi’s $4,244 average = $4,244. Put new covers on the 2 hopper wells at $250 each (low end of HomeGuide’s $250–$500+) = $500. Total: $2,800 + $4,244 + $500 = $7,544. Using Homewyse’s basic range instead for the hoppers (4 x $549–$790 = $2,196–$3,160) would bring the total to $6,940–$7,904.
If you are pricing above-grade windows at the same time, our whole-house window replacement cost guide explains why quotes for the same window can differ so much. For a poured concrete well, the concrete calculator estimates the volume.
Which basement window fits your space
| Room or goal | Good choice | Why |
|---|---|---|
| Unfinished storage or mechanical room | Hopper or glass block | Cheapest; light and some airflow are enough |
| Laundry or workshop | Hopper or small slider | Vents moist or dusty air |
| Finished family room | Larger slider | More daylight and airflow |
| Basement bedroom or habitable space | Code-size slider or casement with a compliant well | Required escape route |
| Security worry at ground level | Glass block | Hard to break through; no operable sash |
DIY vs pro
Reasonable DIY: a same-size swap of a hopper or slider into a sound wood or vinyl buck that sits above grade. You save the $100 to $300 labor charge per window.
Hire a pro when: the buck is rotted, water pools in the well, the opening must be enlarged, or the window has to meet egress code. Those jobs involve excavation, drainage and permits, and a mistake means a leaking foundation.
Safety note: cutting or enlarging an opening in a foundation wall is structural work. Concrete saws create heavy dust and the cut can weaken the wall above if it is not supported and headed correctly. Call a licensed contractor, pull the permit and have the work inspected.
Want more pricing tools? Browse our cost calculators, or compare against what new windows cost upstairs.
Common questions
How much does it cost to replace a basement window?
Most standard basement windows cost $400 to $1,000 each to replace, installed, according to Angi. Homewyse’s September 2026 estimate for a basic in-stock unit is $549 to $790 before permits and contractor overhead.
What size are basement windows?
Angi lists 31 3/4 by 15 3/4 inches as the standard hopper size, and most basement hoppers are 30 to 36 inches wide and 12 to 24 inches tall. Egress-size units run larger, from about 24 by 36 up to 48 by 48 inches.
Do basement windows have to be egress windows?
Not all of them. The IRC calls for at least one escape opening in a basement and one in every sleeping room, with limited exceptions such as a small mechanical-only basement. Other basement windows can be any size. Your local building department has the final say.
Can a hopper window be used for egress?
In practice, no. Even a large 31 3/4 by 23 3/4 inch hopper frame is only about 5.24 sq ft, and egress needs a 5.7 sq ft clear opening once the window is fully open.
How much does a basement window well cost?
For a new well during an egress install, Angi lists $200 to $600 for metal, $250 to $800 for plastic and $750 to $2,500 for concrete. Removing and replacing an existing well runs $1,000 to $5,000 total, per HomeGuide.
Sources
- Angi: Basement window replacement cost, Aug 2026
- Angi: Egress window cost, Aug 2026
- Angi: Standard hopper window sizes, Aug 2026
- Homewyse: Basement window install cost, Sept 2026
- HomeGuide: Window well replacement cost, Feb 2026
- Milgard: Guide to basement windows, Dec 2025
- UpCodes: IRC R310 emergency escape and rescue openings
- EgressUSA: 2024 IRC egress window requirements, June 2026
More guides in Windows.