Description
Chartwell Green uPVC Top Vent and Fixed Casement Window — Understated Ventilation, Maximum View
There is an elegance to a window that gives the room exactly what it needs — no more, no less. Our Chartwell Green uPVC Top Vent and Fixed Casement Window is built around precisely that principle. A single top-hung opening vent positioned discreetly at the upper left provides all the background ventilation the room requires, while the wide full-width fixed lower pane preserves an unobstructed panoramic view across the entire lower section of the frame. The fixed top light on the upper right completes the composition at the head of the frame, maintaining proportional balance across the full width and bringing natural light to the ceiling zone on both sides simultaneously.
This is a window that resolves the tension between ventilation and view more quietly and more completely than almost any other configuration in the range — and it does so through the considered placement of a single opening light rather than through the complexity of multiple active sections.
One Vent, Positioned With Purpose
The single top-hung vent in the upper left section of this window is the only opening light in the frame — and its placement in the upper left rather than the centre or the right is a deliberate decision driven by the specific ventilation dynamic it creates within the room.
A top-hung vent positioned at the upper left extracts warm air from the left side of the room’s upper zone, creating a gentle pressure differential that draws replacement air in from the right side of the space — across the full width of the room. This cross-room air movement is more effective at refreshing the room atmosphere than a vent positioned centrally, which extracts air from above and draws replacement air from directly below rather than from across the room. For rooms where the occupants are typically positioned toward the right side of the window — toward the fixed lower view pane and the furniture that faces it — this left-positioned overhead ventilation is particularly well suited to the way the space is used.
The top-hung opening action makes this vent safe and practical in all weather conditions. Opening outward from its top edge, it tilts away from the frame to create a ventilation gap at the head of the left section through which warm stale air rises and exits continuously. The back face of the open sash acts as a natural rain deflector, directing water away from the gap rather than into the room — making this vent reliable for continuous operation through light rain, overcast conditions, overnight ventilation, and any other situation where the room needs background fresh air without active supervision.
When the room requires more than background ventilation — after cooking, during warm weather, or when a rapid air change is needed — the vent can be opened to its full extent, increasing the airflow while maintaining the same weather-resistant overhead extraction that the top-hung action provides.
The vent is secured in the closed position by a multi-point locking system engaging at multiple points along its perimeter, with a lockable push-button handle as standard. Patented double-action bubble gaskets run the full perimeter of the vent, maintaining a consistent weathertight and draught-proof seal when the vent is closed — ensuring the frame performs as a fully sealed thermal unit in all conditions except when the vent is intentionally open.
The Upper Right Fixed Top Light — Proportional Balance
The fixed top light on the upper right of the frame performs a function that is primarily proportional and secondarily practical — though both contributions are significant. Proportionally, it balances the upper section of the frame across the full width, ensuring that the horizontal rail reads as a continuous element at the same height on both sides rather than appearing on the left with a blank upper right section above it. The two upper lights — vent on the left, fixed on the right — sit at the same height within the same horizontal zone, creating a unified upper band that ties both sides of the frame together at the head.
Without the fixed top light on the right, the frame would read as a casement window with an upper vent on the left and a tall fixed pane on the right with no upper division — a configuration that lacks the proportional refinement of this three-light arrangement. With it, the window has the classic character of a divided-light frame at every section of its width — upper and lower zones clearly defined by the continuous horizontal rail, active and passive elements in the upper zone balanced across both sides.
Practically, the fixed top light contributes natural light to the upper right of the room — the ceiling zone and upper wall above the fixed lower right section — brightening that corner of the room in a way that a frame without an upper right section would not. In rooms where natural light is at a premium, this additional upper right illumination is a meaningful contribution to the overall quality of the interior environment.
The Wide Fixed Lower Pane — View Without Division
The wide fixed lower pane spans the complete internal width of the frame from the left outer stile to the right outer stile as a single uninterrupted panel of A-rated double glazing. This is the dominant element of the window — the pane that occupies the largest portion of the frame, delivers the primary natural light contribution, and frames the view that the window was positioned to capture.
At seated and standing eye level across the full width of the lower section, the fixed lower pane presents the outdoor space as a continuous horizontal view with no vertical division, no meeting stile, and no frame element of any kind interrupting the glazed surface. Whatever lies outside this window — garden, terrace, planted border, open aspect — is visible in its full horizontal extent from left edge to right edge of the lower section, at the height where it is most directly and most comfortably experienced from inside the room.
For rooms that face a particular outdoor space or aspect — where the view is a significant part of the room’s identity and the window’s primary purpose is to frame that view as openly as possible — this single uninterrupted lower pane is the most effective solution. The absence of a central mullion or any vertical division means the outdoor space is never divided into a left view and a right view. It is presented whole, in its full width, continuously — in every season, in every weather, and at every time of day.
The contrast between the single wide lower pane and the two upper lights above the horizontal rail gives this window its quiet architectural authority. The lower section is generous and panoramic. The upper section is refined and proportionate. The horizontal rail between them is the element that makes the relationship between the two zones work — and in the fully sculptured 70mm Chartwell Green profile, it is given the moulded shadow detail that makes it read as a defining design feature.
Thermal Performance — Consistent Across All Three Panes
All three panes in this double glazed uPVC window are specified to the same thermal standard without exception. The 70mm multi-chamber uPVC frame, 28mm argon-filled sealed units, soft coat low-E glass, and warm-edge black superspacer bar deliver a U-value of 1.3 W/m²K consistently across the top-hung vent, the fixed top light, and the wide lower picture pane — meeting Part L Building Regulations throughout and delivering genuine, sustained reductions in heat loss in everyday use.
The horizontal rail crossing the full internal width at mid-height is the thermally critical junction in this window. Our 70mm multi-chamber construction addresses it with sealed air chamber thermal resistance at the rail section, consistent with the outer frame elements and preventing the cold bridge and condensation strip that develop at this junction in single-chamber or thinly profiled alternatives.
The warm-edge black superspacer bar works across all three sealed units simultaneously — replacing the thermally conductive aluminium spacer bar in the sealed unit cavity with a low-conductivity alternative that keeps the glass edge warm and condensation-free in cold weather. Every element of the specification is purposeful, and the combined effect is a window that performs at A-rated standard from corner to corner and from pane to pane.
Chartwell Green — Simplicity Made Sophisticated
On a three-light window with a single opening vent, a fixed top light, and a wide lower picture pane, the character of the frame is expressed through three elements — proportion, profile quality, and finish colour. Our fully sculptured 70mm profile gives all three their fullest expression. The horizontal rail is crisp and shadow-detailed. The upper vent and fixed top light are proportioned to sit naturally within their section of the frame. The outer border is slim enough to maximise the glazed area and strong enough to give the composition its definition.
In Chartwell Green, these qualities are brought together by a finish that adds warmth and heritage character without demanding attention. The soft sage tone runs across the horizontal rail, the central mullion above and below, the outer border, and the vent sash — consistently, quietly, and with the confidence of a colour that has proven itself on every property type and in every context that British domestic architecture presents.
The Chartwell Green finish is co-extruded into the uPVC profile, backed by a full 10-year profile guarantee against fading, peeling, warping, and discolouration. These uPVC casement windows require no painting, no staining, and no maintenance beyond an occasional wipe with a damp cloth.
Security Across All Three Panes
The top-hung vent is secured with a multi-point locking system engaging at multiple points along its perimeter, with a lockable push-button handle as standard. All three panes across the full frame are retained by internal glazing beads, preventing glass removal from the exterior on any section — including the wide lower fixed pane where the glazed area is at its greatest. The fixed sections — upper right top light and lower full-width picture pane — are held in a rigid welded frame with no mechanical entry points. Patented double-action bubble gaskets run the full perimeter of the top-hung vent, maintaining a consistent weathertight and draught-proof seal in all conditions.
Specification at a Glance
- Energy Rating: A-rated | U-value 1.3 W/m²K
- Configuration: 3-light — top-hung vent upper left, fixed top light upper right, wide full-width fixed lower pane
- Frame System: 70mm multi-chamber thermally efficient uPVC
- Glazing: 28mm argon-filled units, soft coat low-E glass, warm-edge superspacer
- Locking: Multi-point locking on top-hung vent
- Handles: Lockable push-button handle as standard
- Beading: Internal across all three panes for maximum security
- Gaskets: Patented double-action bubble gaskets on top-hung vent
- Finish: Chartwell Green — guaranteed not to discolour, warp or peel
- Compliance: Part L Building Regulations
- Guarantee: 10-year profile guarantee
Made to Your Exact Measurements
- Frame Width: 415mm – 700mm
- Frame Height: 800mm – 2200mm
Every window is manufactured to order to your precise dimensions. Enter your measurements at checkout for a perfect made-to-measure fit. Our team is available for sizing queries and configuration advice before you place your order.
When One Vent Is All the Room Needs and the View Should Have the Rest
The best window for any opening is not always the one with the most opening lights — it is the one that gives the room what it actually needs. When the room needs background ventilation and nothing more, and the view outside deserves a wide, uninterrupted frame with no hardware competing for attention across the lower section, this three-light combination is the answer. One top-hung vent handling all the ventilation discreetly at the upper left. One wide fixed lower pane presenting the outdoor space in its full horizontal extent without division. One fixed top light balancing the upper section proportionally across the full width. And the Chartwell Green frame tying all three lights together with the heritage finish and profile quality that make this one of the most quietly resolved and practically intelligent designs in our entire Chartwell Green uPVC window range.
