Bi-Fold Windows

Bi-Fold Windows

Concertina-folding window panes. Serving-hatch to the garden.

Bi-fold windows work like bi-fold doors, scaled down: two to seven window panes that concertina-fold and stack neatly to one side, leaving the entire aperture clear. They’re the defining product for kitchen servery openings onto a patio — and equally at home on pub bars, coffee kiosks, commercial hospitality fit-outs, and any wide-aperture opening where full clear access is the requirement.

Bi-fold windows are a relatively niche specification in standard UK residential work — not every manufacturer makes one. We supply Liniar in uPVC (2–7 panels) and Smart Systems Visofold in aluminium (industry-leading slim sightlines). REHAU does not currently offer a dedicated bi-fold window system.

Why Choose a Bi-Fold Window?

Fully clear aperture when open	All panels fold to one or both sides — unlike a sliding window (where only half the aperture opens) or a casement (where the sash partially obstructs the view). Bi-folds deliver full-width, unimpeded airflow and access.
Serving-hatch application	The classic residential use case — a kitchen window opening onto a patio, with the bottom sill at worktop height. Creates a pass-through between kitchen and garden for drinks, food and conversation.
Commercial hospitality	Pub bars, coffee kiosks, street-food servery windows, garden-centre tills. The aluminium bi-fold window (Smart Visofold) has become the default specification for hospitality openings.
2 to 7 panels	Panel count tailored to the aperture. Wider openings use more panels; narrower openings use fewer. Folds can be to the left, right, or split between both sides depending on the intended use.
Matching bi-fold door look	A bi-fold window next to a bi-fold door delivers a visually coherent indoor-outdoor connection — both fold, both stack, same profile system in matching colour.
Security when closed	Multi-point locking engages on closing. Bi-fold windows are as secure as any other window style when specified correctly.

Profile Systems at a Glance

	Liniar Bi-Fold Windows	Smart Visofold 1000 / 6000	REHAU
Material	uPVC (lead-free)	Aluminium (thermally broken)	Not offered as a window
Panel count	2 to 7 panels	2 to 7 panels	—
Best U-value	1.2 W/m²K (thermal lock technology)	1.5 W/m²K (Visofold 1000)	—
Sightline width	uPVC standard	94mm (Visofold 6000) / 122mm (Visofold 1000)	—
Glazing	Standard double / triple glazed options	28mm sealed units	—
Security	Multi-point locking	PAS 24:2016	—
Nearest REHAU option	—	—	AGILA Multi-Fold Door (bi-fold door, up to 7 panels) for large-aperture applications
Typical use	Residential kitchen servery, cost-conscious commercial	Commercial hospitality, slim-sightline residential	Specify a bi-fold door (AGILA) or tilt-and-turn (GENEO) instead

Liniar Bi-Fold Windows

Liniar’s uPVC bi-fold window range comes in configurations from 2 to 7 panels, tailored to the aperture. The patented Liniar bubble gasket seals all four corners of every pane — eliminating the corner leakage points that compromise conventional bi-fold designs.

Features:

• U-values as low as 1.2 W/m²K thanks to Liniar’s thermal lock technology
• Lead-free uPVC profile matched to the Liniar window range — colour-coordinated with any Liniar casement, tilt-turn or sash on the same elevation
• Full colour-matching to the wider Liniar palette including Anthracite Grey, Chartwell Green, Black, Rosewood and custom foiled finishes
• Unrestricted views when fully opened — no fixed centre mullion blocking the aperture
• Compatible with Liniar uPVC bi-fold doors for a matched opening on the same elevation

Liniar bi-fold windows are specified where a uPVC finish is preferred (cost, thermal performance, matching existing uPVC windows on the building) and where the aperture is residential-scale.

Smart Systems Visofold 1000 & Visofold 6000

Smart Systems’ Visofold range is sold primarily as a bi-fold door system, but the same profiles are widely specified as bi-fold windows in commercial hospitality — pub bars, coffee kiosks, food-service windows — because the aluminium construction delivers slim, tough sightlines that stand up to heavy commercial use.

Visofold 1000

• 122mm sightline, 70mm frame depth
• 28mm glazing, EPDM gaskets, weather brushes
• Uw 1.5 W/m²K — Document L 2010 compliant
• Floating mullion design for clean open views
• Weather performance: Air Class 4 (600 Pa), Water Class E (750 Pa), Wind Class 4 (1800 Pa)
• Security: PAS 24:2016

Visofold 6000

• 94mm sightline — industry-leading slimmest sightline on the market for a bi-fold
• Premium specification for architectural contemporary projects
• Specified where the aesthetic priority is minimum visible frame and maximum glass

Visofold is the right call for pub and restaurant servery windows, garden centre tills, coffee kiosks, and any commercial hospitality opening where aluminium durability and slim sightlines matter more than lowest price.

REHAU — No Dedicated Bi-Fold Window

REHAU does not currently manufacture a dedicated bi-fold window system. The nearest REHAU options depending on requirement:

• REHAU AGILA Multi-Fold Door — a uPVC bi-fold door (up to 7 panels, 9-point locking, Part L compliant at 1.8 W/m²K for doors) — specify if the opening is floor-level and wall-height rather than window-level
• REHAU GENEO Tilt-and-Turn — for large-aperture ventilation on Passivhaus or acoustic-critical installations where a bi-fold window isn’t essential

If you’re specifying a REHAU window package and need a bi-fold window in the same building, the pragmatic approach is to specify Liniar or Smart Visofold for the bi-fold aperture and match the colour across the elevation.

Bi-Fold Window vs Casement vs Sash

	Bi-Fold Window	Casement	Sash
Aperture when open	Full width (all panels stack aside)	Partial (sash covers half)	Half (one sash slides past the other)
Serving-hatch suitability	Excellent	Possible but obstructs	Poor
Aesthetic	Contemporary	Traditional or contemporary	Heritage
Best U-value	1.2 W/m²K (Liniar uPVC)	0.8 W/m²K	1.2 W/m²K
Price position	Premium	Cost effective	Premium
Best for	Kitchen servery to garden, commercial hospitality, wide openings	Mainstream residential	Period / conservation-area residential

Frequently Asked Questions

What’s a bi-fold window used for?

Most commonly, a kitchen-to-garden servery — a window above the worktop that folds fully open to create a pass-through between indoor kitchen and outdoor patio. The same product is specified on pub bars, coffee kiosks, food-service windows and garden-centre tills in commercial hospitality settings.

Are bi-fold windows secure?

Yes. Both Liniar uPVC and Smart Visofold aluminium bi-fold windows include multi-point locking as standard. Smart Visofold 1000 achieves PAS 24:2016. For projects requiring Approved Document Q compliance, confirm specification with our team at point of quotation.

How thermally efficient are bi-fold windows?

Bi-folds have more frame-to-glass ratio than a casement — which makes them slightly less thermally efficient per square metre of aperture. Liniar achieves 1.2 W/m²K; Smart Visofold 1000 achieves 1.5 W/m²K. Both are acceptable under Part L; for the lowest U-values on a given aperture, specify a casement or tilt-turn instead.

Can I match my bi-fold window to existing windows?

Yes. Liniar bi-fold windows are fabricated in the same lead-free uPVC profile as Liniar casements, tilt-turns and sashes — so the colour, foil finish and frame aesthetic match exactly. Smart Visofold aluminium is available in any powder-coated RAL to match any aluminium window or door on the same building.

What’s the maximum aperture for a bi-fold window?

Panel count and size depend on the aperture and manufacturer. Liniar and Smart Visofold both support up to 7 panels. For very wide commercial apertures, Smart Visofold is the right specification due to the additional structural strength of aluminium.

Can bi-fold windows be used instead of bi-fold doors?

They’re different products. A bi-fold window sits above worktop/sill height and is sized like a window. A bi-fold door extends to floor level and is sized like a door. If the aperture is floor-to-ceiling, specify a bi-fold door; if it’s sill-to-head (kitchen servery height), specify a bi-fold window.

Is there a REHAU option?

Not for bi-fold windows specifically. REHAU manufactures bi-fold doors (AGILA Multi-Fold, up to 7 panels) and excellent tilt-and-turn windows, but no dedicated bi-fold window system. On mixed-specification projects, pair REHAU elsewhere on the building and specify Liniar or Smart Visofold for the bi-fold window aperture.

Ready to specify?

Request a quote for bi-fold windows — our team can advise on panel count, profile system (Liniar uPVC or Smart Visofold aluminium), colour matching and configuration for your project.