Types of Windows
The Complete Guide
for Canadian Homeowners

Casement windows consist of a single sash hinged at one side — left or right — that swings outward via a crank handle at the base of the frame. The sash spans the entire opening, meaning there is no fixed centre rail to block the view or restrict airflow.

Because the entire sash presses against the weatherstripping when locked, casement windows form a tighter compression seal than sliding or hung windows. This makes them one of the most energy-efficient operable styles available. The open sash can also be angled to catch a cross-breeze, directing more air into the room than a hung window of the same size.

Where they work best:

• Above kitchen counters or bathroom vanities, where reaching to slide a sash would be awkward — the crank operates from a distance
• In rooms where maximum ventilation is a priority
• Contemporary and modern homes where an uninterrupted glass area is desirable
• Any compass orientation — casements perform well on all four sides of a house

Configurations

Single Casement
One sash, hinged left or right. The most common configuration.

Twin / Double Casement
Two sashes side by side in one frame, each hinged from the outer edge and opening outward.

French Casement
Like a twin casement but meeting at a centre point without a dividing post, creating an unobstructed opening.

Fixed casement (high casement fix)
A casement-profiled sash that is sealed non-operably, used to fill openings where ventilation is not needed but a matching visual profile is wanted.

Awning windows are hinged at the top of the frame and crank open outward from the bottom. The sash extends at an angle, creating a canopy-like overhang — hence the name. Rain falls on the outer face of the glass and runs off rather than entering through the gap, which means awning windows can stay open during light rain without letting water in.

Where they work best:

• Bathrooms: placed high on the wall for privacy while still allowing ventilation
• Kitchens: ventilate cooking odours without the rain risk of a wide-open window
• Basements: provide airflow without the security vulnerability of a low, wide opening
• As a ventilating accent placed above a picture window or below a transom

Hopper windows are the bottom-hinged inverse of awning windows. The sash is hinged at the bottom and tilts inward and downward from the top. They are most commonly found in basements, where the small horizontal opening sits near ceiling height and the inward tilt allows airflow without admitting rain or creating a wide exterior opening.

Hoppers are also used as transom windows above doors or picture windows, where the tilt-in opening provides ventilation in an otherwise fixed composition.

Practical notes:

• Because the sash opens inward and downward, interior clearance is needed below the window
• The inward-tilting sash is easy to clean from inside
• Security is good: the small size and high placement limit entry risk

A single hung window has two sashes stacked vertically: a fixed upper sash and a lower sash that slides upward to open. The upper portion never moves. Screens typically cover the lower operable half.

Single hung windows are among the most familiar window styles in Canada, particularly in older housing stock. They are straightforward to manufacture and maintain, and their classic vertical proportion suits a wide range of architectural styles.

Single hung vs. double hung:

In a single hung window, only the lower sash moves. This reduces cost but limits ventilation — you cannot open the top and bottom simultaneously to create convective airflow (cool air in at the bottom, warm air out at the top), which is possible with a double hung. Cleaning the exterior face of the upper sash may also require access from outside.

Double hung windows are arguably the most common residential window style in North America. Both the upper and lower sashes are independently operable — each can be raised, lowered, or held partially open at any position. Open the bottom for cool air in at floor level, open the top to let warm air escape near the ceiling, or open both simultaneously.

Most modern double hung windows also tilt both sashes inward for cleaning from inside the home — a significant practical advantage in multi-storey houses.

Where they work best:

• Traditional and colonial-style homes where the vertical proportion is architecturally appropriate
• Bedrooms where the top sash can be opened to let warm air escape without creating a ground-level draught
• Second-floor and higher installations where exterior cleaning access is limited
• Homes with young children — opening only the top sash reduces fall risk

Sliding windows have one or more sashes that glide horizontally along a track. They open in the same plane as the wall and do not project outward or inward — a practical advantage where an outward-swinging sash would obstruct a walkway, deck railing, or patio furniture.

Single Slider
One sash is fixed and one is operable, sliding to one side. The most common and economical configuration.

Double Slider
Both sashes are operable, allowing either side to open. Both sashes can be removed for full cleaning access from inside. Also called a "two-panel sliding window".

End Vent
An end-vent configuration places operable sashes on both ends of the frame with a fixed centre panel in between. You get the view of a large picture window with the ventilation of two operable openings.

Where sliding windows work best:

• Wide, low openings where a horizontal proportion suits the space
• Beside patios, decks, or seating areas where a projecting casement sash would interfere
• Ranch-style and mid-century modern homes

Energy performance note:

Sliding windows use a brush seal along the track rather than a full compression seal, which makes them inherently slightly less airtight than hinged windows of comparable quality. Quality weatherstripping and tight track tolerances minimize this difference significantly.

Tilt-and-turn windows are a European design that has become increasingly common in Canada, particularly in newer construction and high-performance renovations. A single sash operates in two distinct modes controlled by rotating the handle:

• Tilt mode: The top of the sash tilts inward approximately 10-15 cm, providing secure background ventilation. The window cannot be entered from outside in this position.
• Turn mode: The entire sash swings inward on the side hinge like an inward-opening casement. The full glass area is accessible for cleaning from inside.

Why tilt-and-turn windows are gaining ground in Canada

• Multi-point locking hardware (typically 5-7 locking points around the perimeter) provides excellent security and a very tight thermal seal
• Both ventilation and full cleaning are accessible from inside — important in high-rise and multi-storey applications where exterior access is difficult
• Very compatible with Passive House and high-performance building standards

Practical consideration

Because the sash swings fully inward in turn mode, furniture cannot be placed directly in front of the window. The inward opening is less intuitive for users accustomed to North American styles, but is quickly learned.

A picture window is a large, single-pane fixed window designed to frame an unobstructed view. There are no dividing rails, no sash mechanism, and typically no grilles or dividers. The entire opening is glass.

Picture windows are among the most thermally efficient options on a per-square-foot basis. The fixed perimeter seal eliminates all air leakage at the sash, and the large glass area can be specified with glazing optimized for direction — high solar heat gain facing south, low solar gain facing west to limit summer overheating.

Where picture windows work best:

• Living rooms, great rooms, and dining rooms with a desirable view
• As the centre panel in an end-vent or combination window arrangement
• Spaces where ventilation is provided by a nearby operable window

A deadlite is a fixed, non-operable glass unit that does not include its own outer frame. The insulated glass unit is installed directly into the rough opening or integrated into a surrounding frame system — for example, beside a door or between two operable windows — without a separate independent frame.

Deadlites are more economical than full picture windows and are commonly used in combination assemblies where a full outer frame would add cost and visual bulk without any functional benefit.

Arched windows have a curved top — typically a semicircular arch, a gothic pointed arch, or a subtler elliptical curve. They draw on centuries of architectural tradition and appear in both traditional and contemporary settings.

Most arched windows are fixed units. For a version that also ventilates, some manufacturers offer a single hung window modified with a fixed arch above it.

Arch variations:

• Full arch (semicircle): The top of the window is a perfect half-circle. Often used over doorways or as a centrepiece above a bay window.
• Eyebrow / elliptical arch: A shallower curve that reads as a gentle arc across the top of a rectangular opening.
• Gothic / pointed arch: Two curves meeting at a point at the top, associated with Gothic Revival architecture.

Round windows — also called circle or porthole windows — are fixed circular units. They admit light in a distinctive pattern and serve as bold architectural accents on gable ends, stairwell walls, garages, and upper storeys of traditionally styled homes.

Variants

• Full circle: a complete round window
• Oval: an elliptical variation
• Octagon: eight-sided, common in Victorian and Craftsman homes
• Quarter-circle: a 90-degree arc, often used in corners or to complete a larger composition
• Circle-top / fanlight: a semicircular unit installed above a rectangular window or door

A transom window is placed horizontally above a door or another window. Historically, the term referred to the structural bar separating the door from the glass above; in common use it now refers to the window itself. Transoms admit additional light into spaces where a full-height window is not possible, and they add a classical proportion to doorways.

Transoms are almost always fixed, though awning and hopper transoms are available when ventilation above a door is wanted.

Where transoms are used

• Above front and interior doors to bring light into hallways and foyers
• Above windows in rooms with high ceilings, where the opening extends toward the ceiling
• In sidelite and transom combinations flanking entry doors
• As clerestory bands — horizontal rows of windows placed near the ceiling to admit light while preserving wall space below