Egress Window Types: Casement vs Slider Comparison Toronto

# Egress Window Types: Casement vs Slider Comparison Toronto

Three operating styles dominate the egress window market in Toronto in 2026: casement, slider (also called horizontal slider), and awning. The choice among them affects the clear opening produced by a given frame size, the air-seal performance, the well clearance required, and the cost. On below-grade Toronto egress installs we install casement windows on roughly 90% of jobs. The reasons are straightforward and worth understanding.

This article compares the three operating styles on the metrics that matter for OBC 9.9.10 compliance and Toronto basement performance, lists the brands and product families we specify regularly (Milgard, Pella, Marvin, Andersen 100-Series), and explains the situations where slider beats casement. For the full project framework, see our [Egress Window Installation Toronto: Complete 2026 Guide](/blog/egress-window-installation-toronto-2026-complete-guide). For the OBC dimensions that drive the comparison, see [OBC 9.9.10 Egress Requirements Toronto](/blog/obc-9-9-10-egress-requirements-toronto).

The Geometry Argument for Casement

The single most important factor in egress operating-style selection is the relationship between frame size (the rough opening the window sits in) and clear openable area (what counts toward 0.35 sq m).

A casement window has a single sash that swings open on a vertical hinge. When fully open, the entire frame interior becomes clear opening. A 36 × 48 inch casement frame produces approximately 30 × 44 inches of clear opening — about 0.85 sq m. Comfortably above OBC.

A slider (horizontal slider) has two sash halves; one is fixed, the other slides horizontally. When the operable half is fully open, the clear opening is half the frame width by the full sash height. A 36 × 48 inch slider produces approximately 17 × 44 inches of clear opening — about 0.48 sq m. Above OBC, but tight on the 380 mm minimum-dimension rule (17 inches = 432 mm, marginal).

An awning window has a single sash that hinges from the top and opens outward. The clear opening is restricted by the hinge geometry and by the open angle the hardware permits. A 36 × 48 inch awning typically opens to 35 to 45 degrees, producing a clear opening that is much smaller than the frame would suggest — often below 0.35 sq m.

For below-grade Toronto egress where every centimetre of opening is constrained by the foundation cut size, casement gives you the most clear opening per dollar of cutting. Slider works only when the frame is generous. Awning is generally not used for primary egress.

The Air-Seal Argument

Casement windows compress against their frame with a continuous weatherstrip when closed. The latching hardware pulls the sash tight at multiple points. This produces the best air-seal of any operating style and is particularly important on Toronto basements where below-grade glass attracts condensation in winter.

Sliders use brush-style weatherstripping where the moving sash meets the fixed sash. Brush seals are effective at blocking large drafts but allow some air infiltration under negative pressure (typical of basements with bath fans, range hoods, or central vacuum running). The slider seals are also more prone to wear over time.

Awning windows, like casements, compress against the frame and produce a good air-seal — but their geometry limits the clear opening as noted above.

For Toronto winters with -20°C nights and basement bedrooms running at 20°C and 50% RH, the air-seal difference between casement and slider can be the difference between dry glass and dripping condensation. Casement is the better thermal performer.

The Well Clearance Argument

Casement windows swing outward when opened. The open sash projects into the window well by approximately the sash width. This means the well must be sized to accommodate not only the person climbing through but also the open sash. A typical 36-inch casement opens to project 30 inches into the well; the 750 mm projection well we install standardly can accommodate this with comfortable clearance.

Sliders open within the plane of the frame — no projection into the well. This means a slider can use a slightly smaller well projection than a casement. On retrofits where the well projection is constrained by setback rules or property line distance, this matters.

Awning windows open outward and upward; the open sash projects into the well at an angle. They're rarely used below-grade for this reason.

The Cost Argument

For a typical 36 × 48 inch egress frame in Toronto in 2026:

• Casement (Milgard, Marvin, or Pella vinyl/fibreglass): $1,200 to $2,200 supply only.
• Slider (same brands, same frame size): $900 to $1,600 supply only.
• Awning (less common in egress sizes): $1,000 to $1,800.

Sliders are 20 to 30 percent cheaper than casements at the same frame size because slider hardware is simpler. For budget-constrained projects where the frame size is generous enough to satisfy 9.9.10 with a slider, the cost saving is meaningful — but it usually disappears when the frame has to be enlarged to compensate, because the foundation cutting is the dominant cost.

When Slider Beats Casement

Slider becomes the right choice when:

• Frame is much wider than tall. A 60 × 30 inch opening is awkward as a casement (very wide sash, hardware strain) and natural as a slider.
• Existing rough opening is wide enough to accommodate a slider with sufficient clear opening. A previous renovation installed a generous opening that needs only a window upgrade.
• Well projection is constrained. Setback or property-line distance prevents the larger well a casement requires.
• Budget is tight on a Tier 1 (replacement-only) job and the frame is generous.

We install sliders on roughly 10% of egress jobs for these reasons.

When Awning Beats Casement

Awning is rarely the primary egress because of the clear-opening limitation. It is sometimes used for:

• Secondary windows in a basement bedroom that do not need to satisfy egress (the egress is satisfied by another window or a door).
• Basement washroom ventilation windows where the small operable opening is fine.

Awning is not typically used as the primary egress on a Toronto basement bedroom.

The Brands We Specify

In 2026 our default specs for Toronto egress windows are:

Milgard Tuscany Series casement. Vinyl frame, dual-pane low-E glass, multipoint locking, made in BC, well-distributed in Ontario. Mid-price ($1,200–$1,500 supply for a 36 × 48). Strong warranty and reliable hardware. Our default for Tier 2 jobs. Pella 250 Series casement. Vinyl frame, similar performance to Milgard, common in Toronto building-supply distribution. Comparable pricing. Used when Milgard lead times are long. Marvin Essential casement. Fibreglass frame, premium thermal performance, slightly higher price ($1,800–$2,200 for the same frame). Used on Tier 3 jobs and on architecturally sensitive exteriors where a fibreglass frame's profile is preferred. Andersen 100-Series casement. Fibrex composite frame, mid-to-upper price, reliable distribution. Used when client preference dictates.

For the well, we default to Boman Kemp galvanized steel wells with composite covers. Sized to the window and the wall projection. Boman Kemp is widely available in Ontario, ships within a week, and has the right ladder accessories for OBC ladder-required wells.

Specification Tips

A few practical specification points we apply on every Toronto egress job:

• Dual-pane low-E glass minimum. SB-12 energy code requires it; better thermal performance on basement windows justifies it.
• Multipoint locking on casements. Better security and tighter air-seal.
• White or beige interior frame colour. Shows less basement dust over time.
• Black or brown exterior frame for brick exteriors; white for siding. Aesthetic match to the surrounding facade.
• Operable mosquito screen. Required for ventilation use; comes standard on most casements.
• Tempered glass if the sill is below 24 inches above floor on the interior side. OBC safety glazing rule.

Conclusion

For Toronto below-grade egress in 2026, casement is the default operating style for clear-opening efficiency, air-seal performance, and well compatibility. Slider is the right call when the frame is generous and budget matters. Awning is for secondary openings, not primary egress.

[Book an egress window consultation](/services/home-renovation/egress-window-installation) and we will spec the right operating style for your specific opening.

For more, see our [Egress Window Installation Toronto: Complete 2026 Guide](/blog/egress-window-installation-toronto-2026-complete-guide), [OBC 9.9.10 Egress Requirements Toronto](/blog/obc-9-9-10-egress-requirements-toronto), and [Window Well Drainage Toronto Design](/blog/window-well-drainage-toronto-design).