Direct-set fixed window
Glass is glazed straight into the outer frame without a sash profile. Gives the narrowest sightline and the largest glass area for a given opening.
Window systems
Aluminium Fixed Windows
An aluminium fixed window is a glazed unit that does not open: the glass sits in a single aluminium frame with no sash, hinges or rollers. That makes it the simplest, most airtight and usually the cheapest window per square metre, and it allows larger glass and slimmer sightlines than any opening window. Metline supplies fixed window profiles in 6063, thermal-break sections and accessories to window fabricators for residential, commercial and façade projects worldwide.
- Frame alloy
- 6063-T5 / T6
- Frame types
- Standard or thermal break
- Glazing
- Single, double, triple, laminated
- Standards
- NAFS · EN 14351-1 · ASTM B221
What is an aluminium fixed window?
A fixed window (also called a fixed light, fixed lite or, when large, a picture window) is a frame and a glazing unit, held in place by glazing beads or structural sealant, with nothing that moves. Its job is to admit daylight, frame a view and keep weather out. Ventilation and escape are provided by other windows or doors in the same opening or room.
Because there is no opening joint, a fixed window has only one weather line to seal: the glass to the frame. Air leakage is typically far lower than for a sliding or casement window of the same size, and the frame can be much narrower because it does not have to carry a sash, lock or hinge. This is why fixed lights are used wherever the designer wants the most glass and the least frame: stair towers, double-height living rooms, shop fronts, hotel lobbies and the upper panes of window walls.
Aluminium suits fixed windows particularly well. A 6063 extrusion is stiff and strong enough to carry heavy insulating glass units over long spans with a frame face of 40 – 60 mm, it holds tight dimensional tolerances, and it can be powder coated or anodised in any colour. With a polyamide thermal break, an aluminium frame also reaches the thermal values required by modern energy codes.
Types of aluminium fixed window
Fixed panel (sash-set)
Glass is set in a fixed sash profile that matches the operable vents beside it, so all panes in a combination look the same from outside.
Picture window
A single large pane, often 2 – 3 m wide, chosen to frame a view. Glass weight and wind load usually govern the frame section and fixings.
Thermal break fixed window
Inner and outer aluminium shells joined by glass-fibre-reinforced polyamide strips, glazed with Low-E double or triple units for energy-code compliance.
Fixed window wall
Several fixed frames mulled together, or a stick-built ribbon of fixed lights between floor slabs, forming a continuous glass wall on low- and mid-rise buildings.
Shaped fixed window
Arched, round, triangular, trapezoid or raked frames made by bending or mitring the extrusions; only possible because the unit does not need to open.
Frame alloys, profiles and thermal breaks
Window frames are extruded almost exclusively from 6063 aluminium. It extrudes at high speed through complex hollow dies, produces a fine surface that powder coats and anodises evenly, and reaches adequate strength after ageing. Where a long mullion or a very large pane needs more stiffness, the section is made deeper or a 6005A or 6061 reinforcing profile is inserted, rather than changing the alloy of the whole system.
| Component | Typical material | Notes |
|---|---|---|
| Frame and glazing beads | 6063-T5 or T6 extrusion to ASTM B221 / EN 755 | Wall thickness commonly 1.4 – 2.0 mm on residential and 2.0 – 3.0 mm on commercial systems |
| Mullions and transoms | 6063-T6, or 6005A-T6 for long spans | Depth chosen to meet deflection limits under design wind load |
| Thermal break | Polyamide PA66 with 25 % glass fibre | Rolled into the profile; shear strength tested to EN 14024 |
| Gaskets and seals | EPDM or silicone | Wedge gaskets on the bead side; structural silicone in some systems |
| Setting blocks and spacers | EPDM or silicone, 80 – 90 Shore A | Placed under the glass at the quarter points or per glass maker |
| Anchors | Galvanised or stainless steel straps and screws | Isolated from aluminium to avoid galvanic attack |
| Frame type | Typical frame U-value (Uf) | Typical use |
|---|---|---|
| Non-insulated aluminium | 5.5 – 7.0 W/m²K | Warm climates, interior screens, utility buildings |
| Thermal break, standard | 2.5 – 3.5 W/m²K | Most temperate-climate housing and offices |
| Thermal break, high-performance | 1.0 – 2.0 W/m²K | Low-energy and passive-house-style buildings |
U-values are indicative ranges for commercially available systems. The certified figure for a given window comes from calculation or testing to EN ISO 10077 or NFRC 100.
Glass options for fixed windows
In a fixed window the glass is around 80 – 90 % of the area, so it decides most of the thermal, acoustic and safety performance. Flat glass weighs about 2.5 kg/m² for every millimetre of thickness, which is why large triple-glazed picture windows need heavier frames and careful handling.
| Glazing | Typical make-up | Centre-pane Ug | Best for |
|---|---|---|---|
| Single toughened | 6 – 10 mm | ≈ 5.7 W/m²K | Interior, warm-climate and utility use |
| Double, Low-E, argon | 6 / 16 Ar / 6 mm | ≈ 1.0 – 1.1 W/m²K | Most housing and commercial projects |
| Triple, Low-E, argon | 4 / 14 / 4 / 14 / 4 mm | ≈ 0.5 – 0.7 W/m²K | Cold climates, low-energy buildings |
| Laminated (PVB or ionoplast) | 6.38 – 12.76 mm or more | As per unit | Safety, security, overhead and floor-level glazing |
| Acoustic laminated IGU | Asymmetric panes, acoustic PVB | As per unit | Roads, rail and airport noise |
| Solar control / tinted | Coated or body-tinted outer pane | As per unit | Reducing solar gain on west and south façades |
Safety glazing is mandatory in hazardous locations: near doors, close to floors, in large panes people may walk into, and in overhead glazing. In North America tempered and laminated glass must meet ANSI Z97.1 or CPSC 16 CFR 1201; in Europe toughened glass follows EN 12150, laminated glass EN 14449, and impact classification EN 12600.
Performance ratings and standards
Windows are rated as complete products, not as profiles. The rating depends on the frame, glass, gaskets, drainage and installation together, so ask for the test report that covers the size and configuration you intend to buy.
| Property | North America | Europe | What it tells you |
|---|---|---|---|
| Product standard | AAMA/WDMA/CSA 101/I.S.2/A440 (NAFS) | EN 14351-1 | Overall performance class and test regime |
| Performance class | R, LC, CW, AW (rising severity) | Declared per property | Suitability for housing, light commercial or high-rise |
| Air leakage | ASTM E283 | EN 1026 / EN 12207 classes 1 – 4 | Draughts and heat loss |
| Water penetration | ASTM E331 / E547 | EN 1027 / EN 12208 classes 1A – 9A, E | Resistance to driven rain |
| Wind load | ASTM E330 | EN 12211 / EN 12210 classes 1 – 5, Exxx | Structural strength and deflection |
| Thermal | NFRC 100 (U-factor), NFRC 200 (SHGC) | EN ISO 10077-1/-2 | Energy-code compliance |
| Acoustic | ASTM E90 / E1332 (STC, OITC) | EN ISO 10140 / EN ISO 717-1 (Rw) | Sound reduction |
Because a fixed window has no opening joint, it usually achieves a higher air and water class than an operable window from the same system. Structural design checks that the frame does not deflect enough to damage the glass seal; a common limit for framing members is span/175 under design wind load.
Surface finishes and colours
Powder coating
Polyester powder in any RAL or custom colour, 60 – 80 µm, to AAMA 2603/2604 or Qualicoat. The standard finish for residential and most commercial windows.
Super-durable and PVDF
AAMA 2604 / 2605 or Qualicoat Class 2 and 3 coatings keep colour and gloss longest in strong sun and coastal air. Specified for façades and high-rise work.
Anodising
Clear, bronze or black anodic film to EN ISO 7599 / Qualanod, class 15 – 25 µm. Gives a metallic look and hard surface that does not chalk.
Wood-grain
Sublimation printed on a powder base coat to look like oak, walnut or teak, for villas and heritage-style projects.
Dual colour
Thermal break frames can be coated in a different colour inside and outside, for example black outside and white inside.
Coastal pre-treatment
Near the sea, specify a high-performance pre-treatment and minimum coating thickness, and plan regular washing.
Fixed windows compared with opening windows
| Factor | Fixed window | Casement / awning | Sliding window |
|---|---|---|---|
| Ventilation | None | Good | Good, half the opening |
| Air tightness | Highest | High (compression seals) | Lower (brush seals) |
| Maximum glass size | Largest | Limited by hinge and sash weight | Limited by roller capacity |
| Sightlines | Narrowest frame | Wider (sash + frame) | Wide interlock |
| Hardware and maintenance | None | Hinges, handles, locks | Rollers, tracks, locks |
| Relative cost per m² | Lowest | Higher | Medium |
| Cleaning outside | From outside or by access equipment | Possible from inside on some types | Possible from inside |
Most real elevations combine both. A typical approach is a large fixed pane for the view, with a casement or awning vent beside or above it for fresh air, or a fixed transom above a sliding door. Building codes also require an openable emergency escape window in some bedrooms, which a fixed light alone cannot provide.
Design and installation points
- Size the frame for glass weight and wind: a 2.4 × 2.4 m triple-glazed unit can weigh over 200 kg; the sill and setting blocks must carry it without rotating the profile.
- Glass bite and edge clearance: keep the glazing rebate deep enough for the unit thickness and its sealant; too little bite is a common cause of seal failure.
- Drainage: even a fixed light needs a drained and ventilated glazing rebate, with weep slots, so water that gets past the outer gasket can escape.
- Thermal movement: allow for frame expansion of about 2.3 mm per metre for a 100 °C range; fix through slotted holes on long frames.
- Perimeter seal: use a compatible backer rod and sealant, or pre-compressed tape and membranes, between frame and wall; this joint fails more often than the window.
- Isolation: separate aluminium from wet cement, steel and copper with tape or coating to prevent corrosion and staining.
- Access for cleaning and replacement: plan how the outside of high fixed panes will be cleaned and how a broken pane would be replaced from inside or outside.
Typical applications
Homes and villas
Picture windows in living rooms, gable glazing, stair windows and clerestories above head height.
Apartments and hotels
Fixed panes beside opening vents in guest rooms, and full-height fixed glass in lobbies and corridors.
Offices and retail
Ribbon windows, fixed shop-front glazing and transoms above entrances, often in thermal break frames.
Schools and hospitals
Laminated fixed glazing in corridors and halls, with acoustic glass on noisy façades.
How to order fixed window profiles from Metline
- Send the scheduleWindow sizes, quantities, elevations or drawings, and the building location and height.
- Set the performanceThermal target (U-value), acoustic, safety and wind-load requirements, and the standard to be met (NAFS, EN 14351-1 or local code).
- Choose frame, glazing pocket and finishStandard or thermal break frame, glass thickness the bead must take, colour and coating standard.
- Approve the submittalWe return section drawings, a profile and accessory list and a quotation on EXW, FOB, CIF or DAP terms.
- Inspect and shipDimensional and coating checks, material certificates for the extrusions, and export packing of profiles with edge protection.
References and standards
- AAMA/WDMA/CSA 101/I.S.2/A440 – North American Fenestration Standard (NAFS)
- EN 14351-1 – Windows and doors: product standard, performance characteristics
- EN ISO 10077-2 – Thermal performance of windows, doors and shutters: frames
- ASTM B221 – Aluminum and Aluminum-Alloy Extruded Bars, Rods, Wire, Profiles, and Tubes
- NFRC 100 – Procedure for determining fenestration product U-factors
Aluminium (aluminum) fixed windows: FAQ
Are fixed windows more energy efficient than opening windows?
Generally yes. With no opening joint they leak less air, and the narrower frame means more of the area is high-performance glass. With a thermal break frame and Low-E argon double glazing, an aluminium fixed window can reach whole-window U-values around 1.4 – 1.8 W/m²K.
How large can an aluminium fixed window be?
Size is limited by glass manufacture, handling, wind load and frame stiffness rather than by the window type. Single panes of 2.5 × 3 m are routine, and larger units are possible with deeper frames, laminated glass and lifting equipment on site.
What alloy are aluminium window frames made from?
6063 in T5 or T6 temper, extruded to ASTM B221 or EN 755. It gives the best surface for powder coating and anodising. Long mullions may use 6005A-T6 or internal reinforcement for extra stiffness.
Can a fixed window be combined with an opening window?
Yes. Fixed lights are often mulled to casement, awning, tilt-turn or sliding vents in one frame, or set as transoms above doors, so the elevation has both a large view and ventilation.
Do aluminium fixed windows need maintenance?
Very little. Wash the frames and glass periodically, keep drainage slots clear, and inspect the perimeter sealant every few years. There is no hardware to lubricate or adjust.
Which glass should I choose for a picture window?
For most climates a Low-E double glazed unit with argon and a toughened or laminated inner pane. Choose triple glazing in cold climates, solar-control coatings on sunny façades, and laminated glass where safety, security or noise control is required.
Need fixed windows for a project?
Send the window schedule, performance targets, colour and destination to sales@metline.in for a frame profile proposal and quotation.
