uPVC Window Styles Explained
All 40 made-to-measure configurations we supply — how each one works, where it fits, and the size range it covers.
Every style below is available in white Rehau Total 70 profile, A+ energy rated, with fire escape hinges, multi-point locking and a 10-year guarantee included as standard. Prices start from around £167 and scale with size.
Terminology: How Windows Are Described
Before the styles themselves, a quick glossary. It saves confusion when you are comparing quotes from different suppliers.
- Light — a single glazed panel. A "2-light" window has two side-by-side panels; a "3-light" has three.
- Sash — the part that opens. Some lights are fixed (do not open), others are sash.
- Top hung — opens outwards, hinged at the top. Common in kitchens, bathrooms and above doors.
- Side hung — opens outwards, hinged on the left or right. Also called a "casement".
- Transom — the horizontal bar dividing a window into top and bottom sections. A "top hung transom" is a narrow opening pane above a larger fixed or sash pane.
- Fixed light — does not open. Used where ventilation is not needed, or paired with sash lights to reduce cost.
Single Light Windows
Top Hung
400–1400mm wide × 400–1300mm tall
The most versatile single-light style. Opens outwards from the bottom edge, hinged at the top. Good for rainy-day ventilation because rain runs off the open sash rather than into the room.
Best for: kitchens above the sink, bathrooms, first-floor windows above ground level where a side hung would be harder to reach.
Side Hung
400–700mm wide × 400–1400mm tall
The traditional casement window, hinged on the right as viewed from outside and opening outwards. Provides the widest unobstructed opening for the frame size, which matters for fire escape compliance in bedrooms.
Best for: habitable rooms at first floor and above where fire escape egress is required, and any narrow-tall opening where a top hung would look squat.
Top Hung Transom over Fixed
400–1400mm wide × 800–2000mm tall
A narrow top hung pane above a large fixed lower pane. Delivers ventilation without sacrificing view, since most of the glass area is unobstructed by a sash frame.
Best for: living rooms and dining rooms where you want the view to dominate and you only need light background ventilation.
Twin Top Hung
400–1300mm wide × 800–2400mm tall
Two stacked top hung sashes: a small transom pane at the top and a full-height top hung below. Used where you need ventilation at two levels in a tall narrow opening.
Best for: stairwells, tall narrow hallways, Victorian proportion openings in period properties.
Side Hung with Fixed Transom
400–700mm wide × 800–1800mm tall
A tall narrow window with a fixed pane at the top and a full height side hung sash below, hinged on the right as viewed from outside. Maximises the opening area for a small footprint.
Best for: utility rooms, W/Cs, narrow back-addition windows.
Side Hung (Left Hinge)
400–700mm wide × 400–1400mm tall
Single pane window hinged on the left (viewed from outside), opening outwards. The largest clear opening per sash.
Side Hung with Fixed Transom (Left Hinge)
400–700mm wide × 800–1800mm tall
A fixed transom over a side hung main pane, hinged on the left (viewed from outside). Suits narrow openings.
Fixed Pane
400–1400mm wide × 400–1300mm tall
A single fixed pane with no opening sash. Maximum glass and the simplest frame, for openings where you do not need ventilation.
Fixed Transom over Fixed
400–1400mm wide × 800–2000mm tall
A fixed transom over a fixed main pane. A non-opening window with the look of a traditional transom.
Fixed Transom over Top Hung
400–1300mm wide × 800–2400mm tall
A fixed transom over a top hung main pane. The main pane opens for ventilation while the transom keeps a traditional look.
Top Hung Transom over Side Hung (Right Hinge)
400–700mm wide × 800–1800mm tall
A top hung transom over a side hung main pane, hinged on the right (viewed from outside). Two opening sashes in a narrow window.
Top Hung Transom over Side Hung (Left Hinge)
400–700mm wide × 800–1800mm tall
A top hung transom over a side hung main pane, hinged on the left (viewed from outside). Two opening sashes in a narrow window.
2-Light Windows
2 Pane Fixed and Side Hung
600–2000mm wide × 600–1400mm tall
The workhorse of modern UK replacement window work. A large fixed pane on the left paired with a side hung sash on the right for ventilation (viewed from outside). Cheaper than two opening sashes and lets more light through.
Best for: lounges, bedrooms, any medium-to-wide opening where one sash is enough.
2 Pane French (Side Hung Pair)
800–1500mm wide × 600–1400mm tall
Two side hung sashes hinged on opposite edges, meeting in the middle. When both are open you get a genuinely wide clear opening. Often called a French casement.
Best for: bedrooms where you want the option to fully open the window onto a Juliet balcony or clear opening, and for fire escape where single-sash egress is marginal.
Twin Top Hung Transoms over Fixed
700–2400mm wide × 800–2000mm tall
A wide traditional look window with two narrow top hung transoms above one large fixed lower pane. An uninterrupted view below, with ventilation from the transoms at the top.
Best for: lounges in 1930s bay-style houses, dining rooms, large feature windows.
2 Pane Fixed with Top Hung Transom over Side Hung
700–2000mm wide × 800–1800mm tall
A large fixed pane on the left, paired with a top hung transom over a side hung sash on the right (viewed from outside). Useful when the opening is wider than a standard 2-light but you do not need a full 3-light.
Best for: awkward intermediate widths, bay side returns, back-addition windows.
2 Pane Top Hung Transom over Fixed with Side Hung
800–2000mm wide × 800–1400mm tall
A top hung transom over a fixed pane on the left, paired with a full height side hung sash on the right (viewed from outside). Generous fixed glazing for the view plus a large opening sash.
Best for: kitchens and dining rooms where you want generous fixed glazing for view plus a large opening sash for ventilation.
2 Pane Top Hung Transoms over Side Hung
800–1500mm wide × 800–1700mm tall
Two stacked lights either side: top hung transom over side hung sash on both halves. Maximum opening area of any 2-light in the range.
Best for: master bedrooms, rooms where cross-ventilation matters, properties near busy roads where the ability to open a small vent at the top while keeping the main sash closed matters.
2 Pane Top Hung Transom over Fixed with Fixed Transom over Side Hung
800–1800mm wide × 800–1700mm tall
Two stacked lights either side: a top hung transom over a fixed pane on the left, and a fixed transom over a side hung sash on the right (viewed from outside). Keeps the transom line level across the window.
Best for: living rooms and bedrooms where you want a level transom line with one opening sash.
3 Pane Fixed, Top Hung Transom over Side Hung, Fixed
1400–2400mm wide × 800–1700mm tall
A wide three light window: full height fixed panes each side, with a top hung transom over a side hung sash in the centre (hinged on the right, viewed from outside). Maximum fixed glass for the view, with ventilation in the middle.
Best for: wide front-room and rear windows where you want the view to dominate.
2 Pane Side Hung and Fixed
600–2000mm wide × 600–1400mm tall
A side hung sash on the left, hinged on its outer edge, and a fixed pane on the right (viewed from outside). A common living room window.
2 Pane Top Hung Transom over Side Hung with Fixed
700–2000mm wide × 800–1800mm tall
A top hung transom over a side hung sash on the left, with a full height fixed pane on the right (viewed from outside).
2 Pane Side Hung with Top Hung Transom over Fixed
800–2000mm wide × 800–1400mm tall
A full height side hung sash on the left, with a top hung transom over a fixed pane on the right (viewed from outside).
2 Pane Fixed Transom over Side Hung with Top Hung Transom over Fixed
800–1800mm wide × 800–1700mm tall
A fixed transom over a side hung sash on the left, with a top hung transom over a fixed pane on the right (viewed from outside).
2 Pane Fixed
600–2000mm wide × 600–1400mm tall
Two fixed panes side by side with no opening sash. For wide openings where ventilation comes from elsewhere.
2 Pane Twin Top Hung
800–1500mm wide × 600–1400mm tall
Two top hung sashes side by side, each opening outwards from the bottom. Rain-friendly ventilation across a wide opening.
2 Pane Top Hung Transoms over Fixed
700–2400mm wide × 800–2000mm tall
Two top hung transoms over two fixed panes, divided down the middle. Ventilation at the top, full view below.
2 Pane Fixed with Fixed Transoms
700–2400mm wide × 800–2000mm tall
Fixed transoms over two fixed panes. A non-opening window with a traditional transom line.
2 Pane Fixed Transom over Fixed with Top Hung Transom over Side Hung
800–1800mm wide × 800–1700mm tall
A fixed transom over a fixed pane on the left, with a top hung transom over a side hung sash on the right (viewed from outside).
2 Pane Top Hung Transom over Side Hung with Fixed Transom over Fixed
800–1800mm wide × 800–1700mm tall
A top hung transom over a side hung sash on the left, with a fixed transom over a fixed pane on the right (viewed from outside).
3-Light Windows
3 Pane Side Hung, Fixed, Side Hung
1400–2200mm wide × 800–1400mm tall
The classic modern picture window: side hung sash, large central fixed pane, side hung sash. Symmetrical, well-ventilated, maximum fixed glass area in the middle for the view.
Best for: living rooms and kitchens with a wide single opening, front elevations on 1970s and later housing.
3 Pane Side Hung, Top Hung Transom over Fixed, Side Hung
1400–2000mm wide × 800–1400mm tall
A side hung sash on each side and a top hung transom over a fixed pane in the middle. Gives the same wide view as a plain 3-light, with a top hung transom for ventilation without opening the main sashes.
Best for: main bedrooms, lounges with a TV wall opposite the window where full sash opening is rarely needed.
3 Pane Top Hung Transoms over Side Hung, Fixed, Side Hung
1400–2400mm wide × 800–1700mm tall
Top hung transoms over side hung sashes on the two outer panes, with a full height fixed centre pane. Designed to match the proportions of original Victorian and Edwardian window openings that are both tall and wide.
Best for: bay window replacements in Victorian and Edwardian properties, front-room feature windows.
3 Pane Side Hung, Fixed, Side Hung with Transoms
1400–2000mm wide × 800–1700mm tall
A side hung sash each side of a fixed centre pane, with a row of transoms above: the centre transom is top hung, the outer two are fixed. Traditional proportions, lots of glass.
Best for: period replacements, feature front-room windows, properties with tall original openings.
3 Pane Fixed, Top Hung Transom over Side Hung, Fixed (Left Hinge)
1400–2400mm wide × 800–1700mm tall
Full height fixed panes each side, with a top hung transom over a side hung sash in the centre, hinged on the left (viewed from outside).
3 Pane Fixed
1400–2200mm wide × 800–1400mm tall
Three fixed panes side by side. A wide picture window with no opening sash.
3 Pane Top Hung, Fixed, Top Hung
1400–2200mm wide × 800–1400mm tall
A top hung sash each side of a large fixed centre pane. A wide window with rain-friendly ventilation at both ends.
3 Pane Top Hung Transoms over Fixed
1400–2000mm wide × 800–1700mm tall
Three top hung transoms over three fixed panes. Ventilation along the top with an uninterrupted view below.
3 Pane Fixed with Fixed Transoms
1400–2000mm wide × 800–1700mm tall
Fixed transoms over three fixed panes. A wide non-opening window with a traditional transom line.
3 Pane Side Hung, Fixed, Side Hung with Top Hung Outer Transoms
1400–2400mm wide × 800–1700mm tall
Side hung sashes each side of a fixed centre pane, with top hung transoms over the side sashes and a fixed transom over the centre.
How to Choose Between Them
A few rules of thumb that shortcut a lot of deliberation:
- Match the original proportions where possible. If the opening is tall and narrow, pick a tall narrow style rather than trying to force a 2-light into a 600mm-wide gap.
- Check fire escape requirements. Habitable rooms at first floor and above need an openable sash at least 450×450mm clear. Side hung sashes usually comply; small top hungs may not.
- More sashes = more cost. A 3 Pane Side Hung, Fixed, Side Hung is cheaper than a 3 Pane with opening transoms, even at the same size, because there is less hardware.
- Fixed glass delivers the best view. If the window faces a garden you want to look at, maximise the fixed-light area and keep sashes for ventilation rather than view.
For more detail on any of these styles, see our uPVC buying guide or call 0800 861 1450 with your opening sizes and we will recommend a configuration.
Rehau Windows in Real Homes
The line-art illustrations above show configuration and hinge direction. Below are photographs of the same Rehau Total 70 profile in finished domestic installations.
Don’t See Your Style?
The 40 styles above cover the vast majority of replacement window openings in UK homes, but they are not everything we can make. We also supply bay and bow windows, arched and shaped frames, French and bifold doors, coloured frames (anthracite, Chartwell green, rosewood and more), triple glazing and larger-than-standard sizes. Get a written quote within one working day — no sales call, no obligation.
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