Chartwell Green UPVC Window-design 26

Chartwell Green uPVC Storm Casement Window — Bold Design, Intelligent Ventilation

Our Chartwell Green uPVC Storm Casement Window takes a classic UK window configuration and elevates it with premium thermal performance, robust security, and the enduring appeal of Chartwell Green. The result is a window that looks considered and architectural on any elevation — while quietly delivering exceptional energy efficiency and year-round comfort inside.

This design is particularly well suited to front-facing rooms, hallways, and first-floor bedrooms where you want generous glazing, flexible ventilation, and a strong exterior presence all in one frame.

Three Lights, Three Purposes

What makes this configuration so practical is that each section of the window serves a distinct function. The two full-height side-hung casements open wide on both sides, giving you powerful cross-ventilation on warm days — the kind of airflow that a standard two-light window simply cannot match across a wider opening.

The central section is split into two zones. The lower portion is a fixed picture pane, keeping the frame uninterrupted and maximising the glazed area for natural light. Above it sits a top-hung opening vent — angled outward from the top — which allows warm, stale air to escape at height while remaining secure and rain-resistant even when left open. It’s the kind of background ventilation that makes a real difference to air quality and condensation control without any draughts at seated or standing level.

Together, the three lights give you complete control over your internal environment at every time of year.

Thermal Efficiency at Its Best

This double glazed uPVC window is built to the same high thermal specification as every window in our range. The 70mm multi-chamber frame, 28mm argon-filled sealed units, soft coat low-E glass, and warm-edge black superspacer bar combine to achieve a U-value of just 1.3 W/m²K — firmly A-rated and fully compliant with Part L Building Regulations.

Every element of the specification works together. The multi-chamber frame traps insulating air pockets within the profile. The argon gas filling slows heat transfer across the cavity. The low-E coating reflects heat back into the room. And the warm-edge superspacer eliminates the cold zone at the glass edge that causes condensation on cheaper units.

The outcome is a window that genuinely reduces your heating demand — not just one that passes a compliance test.

Storm Casement Aesthetics

The term “storm casement” refers to the way the outer casements are hung — set slightly proud of the main frame, with their own sub-frame, giving the window a layered, three-dimensional appearance that has strong roots in traditional British window design. On a Chartwell Green frame, this depth and shadow play is particularly striking, giving the window a hand-crafted, joinery-inspired look that painted white uPVC simply cannot replicate.

The fully sculptured 70mm profile reinforces this aesthetic with clean moulded edges and refined sightlines, while the ultra-slim glazing bars keep the central fixed section as open and light-filled as possible.

Security Built Into Every Detail

All three opening sections — both side casements and the top-hung central vent — are fitted with multi-point locking systems and lockable push-button handles as standard. Internally beaded glazing across every pane means the glass is retained from the inside, removing any possibility of external glazing removal. Patented double-action bubble gaskets maintain a tight, consistent weather seal around every vent, keeping wind, rain and cold air firmly outside.

Specification at a Glance

• Energy Rating: A-rated | U-value 1.3 W/m²K
• Configuration: 3-light storm casement — 2 full-height side-hung casements, central fixed lower pane with top-hung vent above
• 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 all opening lights
• Handles: Lockable push-button handles as standard
• Beading: Internal throughout for maximum security
• Gaskets: Patented double-action bubble gaskets
• 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 made to order to your exact dimensions — simply enter your measurements at checkout. Our team is on hand if you need any guidance before placing your order.

The Smarter Choice for Wider Rooms

When a standard casement isn’t wide enough and a bay window is more than you need, this storm casement configuration hits a practical sweet spot. The wide fixed centre pane keeps your view open and your room bright, the top vent handles everyday background ventilation quietly and securely, and the full-height side casements give you the option of real, generous airflow whenever you want it. It’s one of the most complete and versatile designs in our Chartwell Green uPVC window range — and one that genuinely improves the comfort, security and energy performance of any home it’s fitted to.