In Alberta, every bedroom needs a window or outside door that opens to at least 0.35 m² (3.8 sq ft) with no side under 380 mm (1 ft 3 in), and a window that opens into a window well needs 760 mm (2 ft 6 in) of clear space in front of it (NBC(AE) 2023, 9.9.10.1). That's the second printing of the National Building Code, 2023 Alberta Edition, in force since 17 August 2026 (Government of Alberta, 2026). In Calgary, the City checks bedroom windows at plan review and again at inspection (The City of Calgary, 2022).
Key takeaways
- As of September 2026, every bedroom in Alberta without sprinklers needs a window that opens to at least 0.35 m² (3.8 sq ft) with no side under 380 mm (1 ft 3 in), or an outside door (NBC(AE) 2023, 9.9.10.1).
- A window well needs 760 mm (2 ft 6 in) clear in front of a new window, while Calgary accepts 550 mm (1 ft 10 in) at an existing well when you legalize an existing suite (The City of Calgary, 2026).
- Casement and awning windows count only if they open a full 90 degrees, and Calgary doesn't accept hopper or picture windows as egress (The City of Calgary, 2022).
- Calgary's current advisory allows an egress window under a deck only with at least 760 mm between grade and the deck's underside and the window right at the deck's edge (The City of Calgary, 2022).
- The City's Secondary Suite Incentive Program lists $1,500 for egress windows, but new applications have gone on a waitlist since 24 June 2026 (The City of Calgary, 2026).
- OAF Construction uses $2,000 to $5,000 per opening, window and well included, as its 2026 planning example for adding an egress window in Calgary (OAF Construction, 2026).
What size does an egress window need to be in Alberta?
An egress window must give an unobstructed opening of at least 0.35 m² (3.8 sq ft), with no side under 380 mm (1 ft 3 in), and hold that opening in an emergency without extra support. It must open from the inside without keys, tools or special knowledge, and without taking out sashes or hardware (NBC(AE) 2023, 9.9.10.1).
Both limits apply at once. The code's explanatory note shows it with three openings: 380 mm by 920 mm and 592 mm by 592 mm both give 0.35 m², while 380 mm by 380 mm clears the side rule but gives only 0.14 m² (NBC(AE) 2023, Note A-9.9.10.1.(2)).
The City of Calgary measures the opening with the window in its normal open position, without removing any parts (The City of Calgary, 2022). On a slider, that's the gap the moving sash leaves, not the size of the whole window.
These are the code's egress rules as of September 2026:
| Rule | Value | Clause |
|---|---|---|
| Clear opening | At least 0.35 m² (3.8 sq ft) | 9.9.10.1 |
| Smallest side | 380 mm (1 ft 3 in) | 9.9.10.1 |
| Clearance in a window well | 760 mm (2 ft 6 in) in front of the window | 9.9.10.1 |
| Well cover and security bars | Open from inside without keys, tools or special knowledge | 9.9.10.1 |
| Well drainage | To the footing or another suitable place | 9.14.6.3 |
| Sill height | No maximum; the note recommends 1.5 m (4 ft 11 in) or less | Note A-9.9.10.1.(1) |
Note: code minimums, not recommended sizes. The City of Calgary reviews and inspects them, so confirm your windows with the City before you build.
A high sill can defeat the window even when the opening passes. Where a basement bedroom needs a higher sill, the code's note suggests built-in furniture under the window to reach it.
Which bedrooms need an egress window?
Every bedroom and combination bedroom needs one, on any floor, unless the suite is sprinklered. An exterior door that opens from inside without keys or tools counts instead (NBC(AE) 2023, 9.9.10.1).
The code's note is firm about basements: a basement bedroom in a suite without sprinklers needs its own escape window or door, and the escape path can't run through another room (NBC(AE) 2023, Note A-9.9.10.1.(1)). A window in the rec room next door doesn't count for the bedroom.
For a basement permit in Calgary, your plans must label what each room is for and show the size, type and operation of every bedroom window (The City of Calgary, 2026). For the rest of the room, see the bedroom size guide and, below grade, the basement ceiling height rules.
How big does a window well need to be?
The code sets one number for the well: 760 mm (2 ft 6 in) of clearance in front of the window. Its note calls that "the smallest acceptable clearance" for someone who has to climb out and up, and says to plan for snow in the well (NBC(AE) 2023, Note A-9.9.10.1.(3)). A sash that swings into the well can't eat into that space, so an outward-opening awning needs the 760 mm beyond its open sash.
The well must drain to the footing or another suitable place, and a cover over it must open from inside without keys or tools (NBC(AE) 2023, 9.9.10.1 and 9.14.6.3). The code sets no depth for the well and no ladder rule.
Calgary adds its own rules. This is how the City applies them as of September 2026:
| Situation | Calgary rule | Source |
|---|---|---|
| Existing well, when you legalize an existing suite | 550 mm (1 ft 10 in) clear in front of the window | The City of Calgary, 2026 |
| New window | 760 mm (2 ft 6 in) clear in the well | The City of Calgary, 2026 |
| Window under a deck | 760 mm from grade to the deck's underside, with the window right at the deck's edge | Advisory A19-005, 2022 |
| Window under a cantilever | 760 mm from the cantilever to the top of the well or grade; cantilever projecting no more than 610 mm (2 ft) | Advisory A19-005, 2022 |
| Security bars, or covers and grates over a bedroom well | Not permitted unless reviewed and approved case by case | Advisory A19-005, 2022 |
| Well in a side setback | Up to 0.8 m (2 ft 7 in) into it, and none in the 3.0 m (9 ft 10 in) setback of a laneless lot | The City of Calgary, 2026 |
| Wall within 1.2 m (3 ft 11 in) of a property line | Windows generally not permitted | The City of Calgary, 2026 |
Note: City rules and guidance, not design advice. The City says its advisory bulletins have no legal status, so confirm with the City of Calgary before you build.
Can an egress window go under a deck in Calgary?
Only in a narrow case. Calgary's current advisory, A19-005, allows an egress window under a deck when there's at least 760 mm (2 ft 6 in) between grade and the underside of the deck and the window opening sits immediately beside the deck's edge (The City of Calgary, 2022).
The November 2015 version of the same advisory also allowed a window under a deck with 2.1 m (6 ft 11 in) of headroom between grade and the deck (The City of Calgary, 2015). The City's basements page still links that version, while its suite pages link the June 2022 revision, which no longer lists the 2.1 m option. If a deck sits over a bedroom window on your plan, ask the City before you rely on either version.
Which window types count as egress?
Casement, horizontal slider, vertical slider, awning and tilt-and-turn windows can all work. Picture windows don't open, and Calgary rejects hopper windows because you'd have to crawl over the glass (The City of Calgary, 2022).
Casements and awnings must open a full 90 degrees, clear of obstructions, and an awning must stay open by its own mechanism. An out-swing awning into a window well needs at least 760 mm between the well and the fully open sash. The City's suite pages repeat the 90-degree rule for casements (The City of Calgary, 2026).
Does the City help pay for egress windows?
Only through a waitlist, as of September 2026. The Secondary Suite Incentive Program pays qualifying homeowners up to $10,000 per home to build and register a suite inside the main house, not a backyard suite. Egress windows are one of its safety items, listed at $1,500. ENERGY STAR certified egress windows can add $50 per rough opening, up to $250 (The City of Calgary, 2026).
Since 24 June 2026, new applications go on a waitlist, and funding may not be available. Work done before you apply doesn't qualify, so apply before you cut anything. The legal basement suite guide covers the other suite costs.
What does it cost to add an egress window later?
OAF Construction, a Calgary builder, uses $2,000 to $5,000 per opening as a 2026 planning example for the window, installation and well, or $4,000 to $10,000 for two (OAF Construction, 2026). The spread comes from the window type, digging the well, drainage and extras like steps and metal covers. OAF presents these as planning examples, not quotes.
A new or enlarged window also needs a building permit; a same-size replacement with the same operation doesn't. In a concrete foundation, the City requires an engineer's review if the new opening is wider than 1.2 m (3 ft 11 in), if all openings in the wall add up to more than 25% of its length, or if the wall left between two openings is narrower than either (The City of Calgary, 2026).
What does 0.35 m² look like at full size?
At 1to1 Plans Calgary, your plan is shown at full size on a walkable LED floor, with room names and dimension lines. You can see where each bedroom window sits in its wall and how much clear floor leads to it. Elevations go up on a wall-size screen behind the floor, so you can check each window's drawn size and sill height with your designer or builder.
Changes are made on the spot and shown on the floor right away, and every session is recorded for you to keep. Sessions are quoted for the plan by its size, the quote is free, and there's nothing to pay at booking (get a quote). See renovations and suites, the other room size guides, or book a session.
Questions
What is the minimum egress window size in Alberta?
In Alberta, an egress window must open to at least 0.35 m² (3.8 sq ft), with no side of the opening under 380 mm (1 ft 3 in), as of September 2026. Both limits apply at once, so a 380 mm square opening fails: its sides pass, but its area is only 0.14 m².
How big does an egress window well need to be in Alberta?
In Alberta, an egress window well needs at least 760 mm (2 ft 6 in) of clear space in front of the window. In Calgary, an existing well can keep 550 mm (1 ft 10 in) when you legalize an existing suite, but a new window needs the full 760 mm.
Does every bedroom need an egress window in Alberta?
Yes, every bedroom in Alberta needs an egress window or an outside door unless the suite is sprinklered. That includes bedrooms on upper floors, and a basement bedroom can't rely on a window in another room.
Can you put an egress window under a deck in Calgary?
In Calgary, an egress window can go under a deck only if there's at least 760 mm between grade and the deck's underside and the window sits right at the deck's edge. That's the City's June 2022 advisory; the 2015 version's 2.1 m headroom option isn't in it, so ask the City before you design around it.
Does a sliding window count as an egress window?
Yes, a horizontal or vertical sliding window can be an egress window in Calgary, but only the part that opens counts toward the 0.35 m². The opening the moving sash leaves must be at least 380 mm in both directions.
Is there still City money for egress windows in Calgary?
The City's Secondary Suite Incentive Program still lists $1,500 for egress windows, but new applications have gone on a waitlist since 24 June 2026. Funding may not be available, and work done before you apply doesn't qualify.
Sources
- NBC(AE) 2023, 9.9.10.1 nrc-publications.canada.ca
- Government of Alberta, 2026 alberta.ca
- The City of Calgary, 2022 calgary.ca
- The City of Calgary, 2026 calgary.ca
- The City of Calgary, 2026 calgary.ca
- OAF Construction, 2026 oafconstruction.ca
- The City of Calgary, 2026 calgary.ca
- The City of Calgary, 2015 calgary.ca
- The City of Calgary, 2026 calgary.ca
