Chartwell Green UPVC Window-design 71

Description

Chartwell Green uPVC Twin Top-Hung and Fixed Combination Casement Window — Stacked Ventilation, Undisturbed View

There are window configurations that simply open, and there are window configurations that think about how opening works. Our Chartwell Green uPVC Twin Top-Hung and Fixed Combination Casement Window belongs firmly in the second category. By stacking two top-hung opening lights vertically in the left-hand section — a smaller vent at the top and a generous opening casement below it — this four-light design creates a ventilation arrangement of unusual capability and flexibility, while dedicating the entire right-hand section to a clean, unobstructed fixed glazing that keeps the view open and the room bright.

This is a window that rewards the rooms it is fitted in — rooms where air quality, natural light, and the character of the frame all matter — with a configuration that works harder than its appearance suggests.

Two Top-Hung Lights, One Left Section

The left-hand section of this window is divided by a single horizontal rail into an upper and lower zone, each containing a top-hung opening light. This stacked arrangement of two top-hung vents in the same vertical section is what distinguishes this design from every other combination casement in the range — and what gives it its exceptional ventilation capability.

The upper top-hung vent is the smaller of the two lights. Opening outward from its top edge, it creates a narrow ventilation gap at the head of the upper left section through which warm air rises and escapes continuously. The top-hung action means this vent is rain-resistant by design — water runs off the back of the open sash rather than entering the room — making it the ideal always-on background ventilation light. Left open overnight, during cooking, after bathing, or throughout a working day at home, it maintains a constant gentle exchange of room air without draughts, without noise, and without any need for supervision or adjustment.

The lower top-hung casement is significantly larger — occupying the full lower height of the left section below the horizontal rail and the full width of the left section from the outer frame to the central mullion. When opened, it swings outward from its top edge across a considerably greater arc than the upper vent, creating a large triangular ventilation aperture at the lower left of the frame. The volume of air that can pass through this opening is substantially greater than through the upper vent alone — making it the active ventilation light for warm days, post-exercise recovery, kitchen ventilation during cooking, and any situation where a genuine change of room air is needed quickly.

Both top-hung lights open and close completely independently. The upper vent can be open while the lower casement is closed — providing continuous background ventilation without the larger opening. The lower casement can be opened while the upper vent is closed — providing active high-volume ventilation at lower frame height. Both can be open simultaneously for the maximum combined ventilation effect, with warm air escaping at the head of the upper section and fresh air entering through the large lower aperture simultaneously.

This independent dual-level top-hung ventilation arrangement, concentrated entirely in the left-hand section of the frame, gives this window a practical capability that no combination window with a single opening light can match — and it does so through the cleanest and most weather-resistant opening mechanism available in the casement window family.

Why Top-Hung Throughout

The decision to use top-hung opening lights for both vents rather than mixing top-hung and side-hung configurations is deliberate and practically motivated. Top-hung opening lights are inherently rain-resistant — the back of the open sash acts as a natural weather deflector — making them the most reliable choice for lights that will be left open for extended periods without supervision. They do not protrude sideways from the frame, eliminating any risk of contact with adjacent walls, fences, or passers-by. And when open, the gap they create is at the top of the pane, directing airflow upward toward the ceiling and allowing it to mix with room air gradually rather than entering as a direct horizontal draught at face level.

For a window that concentrates all ventilation function in a single vertical section, using top-hung lights throughout also gives the left-hand section a visual consistency — both opening lights read as the same type, the same depth, and the same profile detail, creating a left section that looks intentional rather than assembled from mismatched components.

Fixed Right Section — Light Without Interruption

The right-hand section of this window is given entirely to fixed glazing — a full-height fixed pane below and a fixed top light above, separated by a horizontal rail at the same height as the rail on the left section, and together spanning the complete height of the right-hand frame from sill to head.

The full-height fixed lower pane is the primary light source for the room from this window. Running from just above the sill to the horizontal rail without any handle, hinge, or vent indicator in the glazed area, it delivers a wide, clean view at seated and standing eye level and floods the room with natural light across the right-hand section of the opening. For rooms where the outlook on the right side of the opening is the view worth preserving — a garden, a terrace, a planted aspect — this fixed pane ensures the window frames that view without competing with it.

The fixed top light above the rail completes the right-hand section at the head, sitting at the same height as its counterpart above the lower top-hung casement on the left. This height consistency ties the two sections of the window together across the horizontal rail — making the four-light composition read as a single resolved frame rather than an active left section and a passive right section pushed together.

Consistent A-Rated Thermal Performance

All four panes in this double glazed uPVC window are built to the same thermal specification 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 across the full four-light frame — A-rated performance meeting Part L Building Regulations throughout.

The horizontal rail is thermally critical in a window with two stacked opening lights, because it spans the full width of the left section as a continuous frame element and creates a potential cold bridge between the inside and outside surfaces. Our 70mm multi-chamber profile handles this with the same sealed air chamber construction used throughout the outer frame — maintaining thermal resistance at the rail consistent with the rest of the frame and eliminating the cold strip and condensation risk that appears at mid-frame rails in lower-specification windows.

Chartwell Green — The Frame That Ties It Together

The four-light layout of this window — twin stacked top-hung lights on the left, twin stacked fixed lights on the right — has a clear bilateral logic that the Chartwell Green frame reinforces and resolves. The horizontal rail running continuously across the full width at the same height on both sides is the key design element, and in the fully sculptured 70mm profile it is given the shadow detail and moulded depth that make it read as a positive design feature rather than a structural necessity.

The soft sage tone of Chartwell Green sits across the full frame with the quiet authority of a finish that belongs on a quality window — warm enough to give the elevation character, restrained enough to let the glazing and the view do their work. These uPVC casement windows carry the co-extruded Chartwell Green finish with a full 10-year profile guarantee against fading, peeling, warping, and discolouration, and require nothing beyond an occasional wipe with a damp cloth to maintain their appearance across the full lifespan of the frame.

Both top-hung opening lights can be cleaned on their outer faces from inside the room when open — a practical advantage that becomes more valuable the higher the window is positioned in the wall.

Security on Both Opening Lights

Both top-hung opening lights are independently secured with multi-point locking systems engaging at multiple points along the opening perimeter of each light. Lockable push-button handles are fitted to both opening lights as standard. All four panes across the full frame are retained by internal glazing beads, preventing glass removal from the exterior on any section. Patented double-action bubble gaskets run the full perimeter of both top-hung lights, maintaining a consistent draught-proof and weathertight seal in all conditions — including when only one of the two left-hand lights is in use.

Specification at a Glance

• Energy Rating: A-rated | U-value 1.3 W/m²K
• Configuration: 4-light — top-hung vent upper left, fixed top light upper right, large top-hung casement lower left, full-height fixed pane lower right
• 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 both top-hung opening lights
• Handles: Lockable push-button handles on both opening lights
• Beading: Internal across all four panes for maximum security
• Gaskets: Patented double-action bubble gaskets on both opening lights
• 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, configuration advice, and guidance on whether twin top-hung or mixed opening styles best suit your specific opening before you place your order.

When Ventilation Needs to Work at Every Level Without Compromise

Most combination casements give you one opening light — one type of ventilation, one height level, one set of trade-offs between background airflow and active circulation. This twin top-hung configuration gives you two — stacked vertically in the same left-hand section, operating independently, covering every ventilation need from continuous background refresh to high-volume active air change — all through the most weather-resistant opening mechanism available. The right-hand fixed section keeps the view open and the room bright throughout. And the Chartwell Green frame gives the whole design the finish and profile quality that make it one of the most practically capable and visually resolved windows in our entire Chartwell Green uPVC window range.