4-pane fixed window, made to measure

This window is the wide version of the 3-pane fixed window, with a fourth fixed pane added. All four stay fixed. That suits a wall designed mainly for light and view, with ventilation handled elsewhere in the room — by a door, a sliding patio door or another window. How wide a single pane can be without a mullion in the profile you choose is shown in the configurator.

The standard size is 3,200 × 1,500 mm, split equally across the four panes; in the configurator you set your own size. If you want to be able to ventilate in the same width, the 4-pane window with one tilt and turn sash and the 4-pane window with two tilt and turn sashes are the same layout with one or two opening sashes.

The description of this layout gives up to 6 metres wide as the upper limit for four fixed panes side by side — well beyond the standard size of 3,200 mm that the configurator starts from. At that width each pane is so large that the glass becomes the heaviest part of the window; how far you can actually go depends on the profile and the type of glass you choose, and the configurator shows you as soon as you enter a size.

With four panes side by side, it pays to decide beforehand whether you want equal panes or a different rhythm — two wide outer panes with two narrower ones in the middle, for example. That is a design choice, not a technical requirement: all four stay fixed, so no split costs more hardware than another. If you do want to ventilate somewhere across these four panes, the 4-pane window with one tilt and turn sash and the 4-pane window with two tilt and turn sashes are the same width with that difference built in.

On a window this wide, it pays to measure the opening in several places — left, centre and right — because a wall that isn't quite square over three metres is not unusual. If in doubt, give the smallest measurement: a window ordered slightly too narrow can still be made good with packers or an add-on profile; one ordered too wide fits nowhere.

Of all the 4-pane windows, this one needs the least maintenance: no hardware anywhere across the full 3,200 mm. Colour and finish come from the same chart as any other pane — any RAL colour in aluminium, a foil or through-colour in uPVC — and with four identical fixed panes, one continuous colour is the usual choice for the calmest look across the full width of the wall.

In a renovation, this window often replaces several separate, older windows with one continuous area of glass. In a new build, this width is usually fixed early in the design, because an opening of 3,200 mm or more affects the structure above it — something the architect and the structural engineer look at together, not something that gets changed afterwards.

For security, all four panes are fixed — no hardware to force, only glass across the full width. On the ground floor, laminated or safety glass is where you get any extra resistance.

Because all four panes are fixed, you can use the heaviest, best-insulating glass across the full width without any consequence for hardware. That makes this window a logical choice where insulation matters more than ventilation in this part of the wall.

Still not sure? Use the comparison with the other layouts in this group, above, to see which arrangement suits your situation best.