IGU Configuration for Sliding Doors & Windows | EZZO.SG

Home › Blog › Choosing IGU for Sliding Systems Glass Technology How to Choose the Right IGU Configuration for Aluminium Sliding Doors & Windows By EZZO.SG Editorial · 22 July 2025 · 8 min read · Glass Technology Most glass guides treat sliding and casement systems as interchangeable — as though the same 5+20A+5mm IGU drops equally into a TY150 sliding door and a fixed casement. It does not. Sliding systems impose a distinct set of constraints that casement panels simply do not face: panel weight limits tied to roller and track capacity, frame depth ceilings that cap how thick an IGU can physically be, and cavity width choices that ripple directly into panel area calculations. Choose the wrong IGU for a sliding system and you do not just underperform thermally — you risk premature roller wear, panel racking, and voided system warranties. This guide walks through each constraint systematically, then maps the result to every EZZO.SG sliding door and window model. Sliding System Fundamentals — What Affects IGU Choice A casement window swings on a hinge. The hinge assembly carries the full panel load, and the glass specification affects performance but rarely stresses the hardware beyond its rated limits — because the panels are small by comparison. Sliding doors and windows operate on an entirely different mechanical principle: each panel rides on a carriage of bottom rollers (and sometimes top rollers in flush-track systems) running along precision-machined tracks. Everything about that carriage has a weight limit. When you increase IGU thickness — say, from a 5+12A+5mm (22 mm total) to a 5+20A+5mm (30 mm total) — you are adding 8 mm of cavity width, which adds direct mass to the panel. For a modest 1.2 m × 2.1 m sliding door panel, moving from a 22 mm unit to a 30 mm unit adds approximately 10–12 kg to panel weight. That change can represent a 12–18% increase in roller load for a mid-weight panel, and if the roller is already near its rated maximum, that margin disappears quickly. Four variables interact to determine what IGU you can actually specify: Frame rebate depth — the physical groove in the aluminium profile that receives the IGU. This hard-limits maximum IGU thickness regardless of any other consideration. Roller and track capacity — the rated panel weight your sliding hardware can carry. Specified by profile manufacturer; cannot be exceeded without hardware upgrades. Panel area — larger panels are heavier by default; glass is approximately 2.5 kg per m² per millimetre of thickness, so a 5+27A+5mm unit weighs 37 × 2.5 = 92.5 kg/m² of glass alone. Configuration (single-track, double-track, triple-track) — how many panels share a track bay determines how weight distributes across the carriage system. Key principle: For sliding systems, always start with the profile — not the glass. The frame defines the IGU envelope; the glass fills it. Trying to work backwards from a desired glass specification and hoping the frame accommodates it is the most common source of expensive mistakes. Profile Depth and Maximum IGU Thickness Every EZZO.SG sliding profile has a defined glazing rebate. This dimension — how far the glass groove extends into the frame cross-section — sets an absolute ceiling on IGU overall thickness. The rebate must be deep enough to hold the IGU securely under the lateral loads generated by wind, thermal expansion, and daily operation, with a minimum of 10 mm of glass engagement on each side of the frame. This means the specified IGU thickness cannot be pushed to the physical limit of the rebate; a 5–8 mm tolerance must be maintained. The following table maps every current EZZO.SG sliding door and window model to its maximum practical IGU specification: EZZO sliding system profile depth and maximum IGU compatibility Model Frame Width Wall Thickness Max IGU Specification Total IGU Thickness Notes TY150 Sliding Door 150 mm 5.0 mm 5+27A+5mm or triple-pane laminated 37 mm (std) / 47–52 mm (triple) Max panel height 7 m; high-rise/large-span preferred TY120 Sliding Door 120 mm Frame 2.0 mm / Panel 2.0–4.0 mm / Hook 3.0–6.0 mm 5+20A+5mm standard; 5+15A+5mm with premium LOW-E 30 mm (standard) / 25 mm (LOW-E variant) Max panel height 4 m; standard residential E127 / E190 Sliding Door 127 mm / 190 mm 4.0 mm 5+20A+5mm 30 mm E190 suited for wider-span panels; same IGU max Sliding Window 130 (side press) 130 mm 2.0 mm 5+20A+5mm 30 mm Triple-sealed at 700Pa; rolling screen integrated Sliding Window 123 (broken bridge) 123 mm 2.0 mm 5+15A+5mm 25 mm Frame-encased panel; thermal-break profile Sliding Window 112 112 mm 1.4 mm 5+12A+5mm 22 mm Standard residential window; lighter wall construction All standard configurations use tempered safety glass. Laminated outer panes, argon gas fill, and LOW-E coatings are available across applicable models subject to profile rebate depth verification. The practical upshot: if you want the widest possible cavity (and therefore the best thermal and acoustic performance), the TY150 is your only option for achieving 5+27A+5mm in a sliding door. The TY120, E127/E190, and Sliding Window 130 all cap out at 5+20A+5mm — still a capable specification, but one that should be matched with argon fill and LOW-E coating to maximise what the available 30 mm envelope delivers. Panel Weight and Glass Configuration Glass weighs approximately 2.5 kg per square metre per millimetre of thickness. For an IGU, you add the mass of both panes. A 5+20A+5mm unit therefore contributes 25 kg per square metre of glass area (10 mm of total glass × 2.5 kg/m²/mm). The argon cavity and spacer assembly add a further 0.5–1.0 kg/m². For a standard 2.4 m × 2.1 m sliding door panel (5.04 m² panel area), that puts the glass mass alone at approximately 126–130 kg before frame weight is added. 25 kg/m² Glass mass in 5+20A+5mm IGU (glass only) ~30 kg/m² Glass mass in 5+27A+5mm IGU (glass + spacer) +12–15 kg Typical weight increase per panel: 20A → 27A cavity For double-track sliding configurations — where two panels run on independent tracks and neither panel carries the other's weight — this is manageable within standard roller ratings. For triple-track configurations (common in larger openings where panels stack), the calculation changes: if all panels can park in the same bay simultaneously, the track section carrying the stacked panels must handle two or three panels' combined weight. This is where IGU specification decisions have direct engineering consequences. Laminated outer panes compound the weight issue further. A laminated 5mm+PVB+5mm outer pane effectively doubles the outer glass thickness — contributing 25 kg/m² for the outer pane alone rather than 12.5 kg/m². On large sliding doors (above 3 m²), the choice to laminate must be weighed against roller and track capacity, or a hardware upgrade must be budgeted alongside the glass upgrade. Practical check: Before specifying laminated outer panes or a 5+27A+5mm unit on any sliding panel larger than 2.5 m², request a written confirmation from EZZO.SG's engineering team that the roller and track specification for your chosen profile is rated for the resulting panel weight. This takes one business day and avoids expensive hardware retrofits after installation. Start with Climate — Solar Heat Gain is Public Enemy #1 Sliding doors and windows are almost always large openings. A standard two-panel sliding door might present 4–6 m² of glass to the outside. At Singapore's latitude, a 5 m² west-facing glass surface with no solar control can transmit 2–3 kW of heat into your living space on a clear afternoon — roughly equivalent to running six hairdryers simultaneously. Your air-conditioning runs against that load all day. This is why the primary IGU specification decision for any Singapore sliding system is always solar control, not aesthetics. The metric to optimise is Solar Heat Gain Coefficient (SHGC) — the fraction of incident solar radiation that passes through the glazing assembly and enters the buildi