Slimline aluminium windows
Slimline aluminium windows show less frame and more glass than uPVC. Our slimmest opening window shows 89 mm of frame and casement together, against 119 mm in uPVC. We make them to your size, opening inwards as tilt and turn or side-hung.
Slim profile aluminium windows
The Reynaers ConceptSystem 77 shows 89 mm of outer frame and casement together. The Reynaers MasterLine 8 and the Aluprof MB-Ferroline both show 97 mm.
Ultra slim aluminium windows
The Reynaers SlimLine 38 shows 33.5 mm of outer frame, 105.5 mm with the opening part and 52 mm on a fixed light. It recreates the lines of old steel windows, at Uf 1.9 W/m²K for the frame.
Modern aluminium windows with a flat face
In the Hidden Vent style of the ConceptSystem 77, the opening part disappears completely behind the frame, for a clean, flat face. From outside an opening window then looks much like a fixed one.
Slimline and insulation
Slim costs insulation. The MB-Ferroline has Uf 1.50, the MB-86N 0.57 with a 122 mm sightline. As a fixed light the MB-86N shows only 59 mm, and it goes up to 6,000 × 3,000 mm.
Aluminium windows design
A modern window keeps divisions few and panes large. Dark RAL colours such as RAL 7016 or RAL 9005 make the frame read as a thin line; inside can be white.
Slimline aluminium windows UK: supply only
You put the window together in the configurator and request a made-to-measure quote. We supply and don't install; delivery to the UK is quoted with your offer.
Large fixed panes in a slim frame
Fixed glass has no sash, so it shows the least frame of anything in a window: 52 mm on the SlimLine 38 and 64 mm on the ConceptSystem 77, next to the 59 mm of the MB-86N above. A modern layout makes use of that with one wide fixed pane and a narrower opening part only where you want air.
Mullions and transoms
Where two panes meet inside one frame there is a T-section. It is 48 mm wide on the SlimLine 38, 76 mm on the ConceptSystem 77 and 80 mm on the MasterLine 8. Every division adds one of these lines to the elevation, so a modern window keeps them to a minimum.
Tall sashes and big openings
Reynaers sets its limits per sash rather than per window. On the ConceptSystem 77 and the SlimLine 38 a window sash can be up to 2,800 mm high and 170 kg; on the MasterLine 8 up to 2,800 mm and 200 kg. Opening parts in our configurator are up to 1,400 mm wide.
The opening type sets limits too. A tilt and turn or side-hung sash needs to be at least 500 mm high, because below that a handle with its corner drives doesn't fit. A hopper stops at 1,200 mm high, the limit of the stay that holds it.
Steel-look aluminium windows
Two of our profiles copy the thin lines of steel windows in aluminium. The SlimLine 38 comes in four styles, Classic, Cubic, Ferro and Functional; the MB-Ferroline has a steel-look nose on its 110 mm deep frame. Neither is steel, so there is nothing to rust and no paint to keep up.
Glass in slimline aluminium windows
With large panes, the glass is most of what you look through and most of what insulates: Ug 1.1 for HR++ double glazing, Ug 0.6 for HR+++ triple. Part L looks at frame and glass together, so on a slim profile with a higher Uf, such as the MB-Ferroline at 1.50, the choice of glass carries more weight in the result.
Hinges and handles
On a tilt and turn or side-hung window you can have concealed hinges. They are housed in the rebate, out of sight once the window is closed, which keeps the inside as clean as the outside. A hopper has no hinges to hide; it tilts on a stay arm. Anthracite hardware is only available on aluminium, and the hardware colour can differ from the frame.
Frequently asked questions
Why are aluminium windows ideal for modern homes?
Aluminium is stronger than uPVC, so the frame can be slimmer and larger, and any RAL colour is possible. That gives more glass and less frame.
What are the best aluminium windows for modern homes?
The slimmest is the ConceptSystem 77 at 89 mm; the best insulating is the MB-86N at Uf 0.57. Choose on which of the two matters more to you.
Do slimline aluminium windows meet Building Regulations?
That depends on the whole window, frame and glass, not on the frame alone. In England a replacement window needs a U-value of 1.4 W/m²K or WER band B; the Uw of your window is in the quote.
Can slimline aluminium windows take triple glazing?
Yes. The ConceptSystem 77 takes glass up to 53 mm thick and fits triple with a different glazing bead, and the MasterLine 8 has an HI+ version meant for triple. Triple weighs 30 to 36 kg per m², so it adds load to every sash.
Do you make aluminium windows that open outwards?
No. Ours open inwards, as tilt and turn or hopper, and from two panes one can be a full-opening side-hung window; the rest is fixed. Some of the systems exist in an outward-opening version, but we don't supply it.
Can one slimline frame hold fixed and opening panes?
Yes. You set the type pane by pane in the configurator. If you want the fixed pane to look like the opening one beside it, choose a fixed sash: the same sash frame, without hardware, that doesn't open.
Know what you want? Put it together.
No form first: you watch your window take shape as you choose. The price follows in the quote, within three working days.
Configure your window or door
Where we have a guide price, it is on the page, not behind a form — not a quote and not a final price; the amount for your sizes is in the made-to-measure quote.
Request a quote