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:
| Model | Frame Width | Wall Thickness | Max IGU Specification | Total IGU Thickness | Notes |
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| 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.
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 building as heat. A bare clear-glass 5+20A+5mm unit has an SHGC of approximately 0.63. The same unit with a standard single-silver LOW-E coating drops to approximately 0.35–0.40. A double-silver LOW-E coating pushes it further to 0.25–0.30, cutting solar heat gain by more than half relative to clear glass — while maintaining visible light transmission above 60%.
- West and north-west facing sliders receive the most intense afternoon sun in Singapore and generate the highest air-conditioning loads. Double-silver LOW-E is the minimum specification.
- South-facing sliders have lower solar load and can often tolerate single-silver LOW-E or even a clear IGU where natural light is a priority.
- East-facing sliders take morning sun — less intense than the west, but still significant. Standard LOW-E suffices for most cases.
- North-facing sliders (Singapore north-facing means minimal direct sun) can prioritise visible light transmission over solar control — a tinted clear IGU or standard LOW-E is appropriate here.
Add Noise Protection for Specific Locations
Singapore's urban density means most properties sit within earshot of at least one significant noise source. But not every room facing a noise source requires the same acoustic specification. A bedroom above a ground-floor car park needs different treatment from a living room backing onto a canal. The decision framework here is location-specific, not property-wide.
Three noise categories drive different IGU responses in sliding systems:
MRT lines (underground and elevated). The Thomson-East Coast, Circle, and North-South/East-West lines all generate characteristic low-frequency structural rumble (63–125 Hz) and higher-frequency steel-on-steel screeching at bends. For properties within 150 m of track, an asymmetric IGU — where the two glass panes are of different thickness — is more effective than matched panes, because the differing natural frequencies prevent resonant build-up. A 6+20Ar+5mm or 8+22Ar+5mm configuration is worth specifying if your profile rebate allows it.
Major expressways (CTE, PIE, AYE, BKE, KPE). Road traffic noise peaks in the 500–2000 Hz mid-frequency range. Standard 5+20A+5mm argon-filled IGU with LOW-E achieves Rw 30–33 dB, which is sufficient for properties above 300 m from the carriageway. For frontline units below 200 m, upgrading to 5+22Ar+5+PVB+5mm (acoustic laminated triple configuration) adds 6–9 dB Rw and renders most traffic noise below awareness threshold at night.
Flight paths (Changi, Seletar approaches). Aircraft noise is broadband but peaks at low-mid frequencies (100–800 Hz). The key improvement here comes from total glazed mass and cavity decoupling. A 5+27A+5mm unit offers meaningfully better aircraft noise attenuation than 5+20A+5mm due to the wider mechanical decoupling distance between panes — an argument for specifying the wider cavity in TY150 systems on affected elevations.
Match Security Glass to Access Points
Sliding doors — particularly ground-floor and balcony-level panels — represent the primary physical access points in most Singapore homes. The IGU specification at these locations should reflect that reality. Not every panel needs security glass, but specific positions absolutely do.
Ground-floor sliding doors. The outer pane should always be laminated tempered glass. Lamination (PVB or SGP interlayer between two glass plies) means that even if the glass is broken, the interlayer holds the fragments in place. A single kick or hammer blow that would create an instant entry point through standard tempered glass leaves only a crazed interlayer on a laminated panel — buying critical seconds and deterring opportunistic break-ins. This is not gold-plating; it is basic physical security.
Balcony and pool-facing sliders. BCA Approved Document requirements mandate that glazing in barriers and balustrades meets impact safety standards. Sliding doors that serve as the primary barrier between an occupied floor and an open balcony — particularly where the door threshold is low — should use laminated glass on both panes. The combination of tempered + laminated (also called "safety laminated") on both surfaces provides the highest level of post-breakage safety and is the specification used in EZZO.SG's high-specification installations.
Hook rails and multi-point locks. The glass specification interacts with your locking hardware. Multi-point locking bars apply clamping force along the full height of the panel, which slightly flexes the glass under load. Very thin outer panes (4 mm) in large panels can develop micro-cracks at the engagement points over time under this loading, particularly in taller sliding doors. EZZO.SG's standard minimum is 5 mm for all sliding panel glass to provide sufficient stiffness margin. Where multi-point hook locks are specified on panels above 2.5 m height, a 6 mm outer pane is recommended.
Budget Trade-offs — Where to Invest vs Save
The full range of IGU options spans a significant cost envelope. A clear 5+12A+5mm unit in a Sliding Window 112 sits at one end; a laminated argon-filled double-silver LOW-E triple configuration in a TY150 door sits at the other. Most projects land somewhere between, and the right answer is not always "specify the best IGU in every opening." It is: allocate your glass budget to the openings where it delivers the most measurable impact.
The minimum sensible specification for any Singapore sliding system. Air fill is acceptable at entry level; the LOW-E coating is not optional. Without it, solar heat gain in a typical 4 m² west-facing slider adds 1–1.5 kW to your cooling load continuously. This tier suits north-facing and east-facing panels where solar load is moderate.
Upgrading to argon and double-silver LOW-E costs approximately 15–20% more than standard LOW-E air-fill but reduces SHGC from ~0.38 to ~0.27 and improves U-value by 10–15%. This is the recommended specification for west-facing, south-facing, and any opening above 3 m² regardless of orientation. The energy payback in Singapore's climate is typically under three years.
The specification for large west-facing sliders above 4 m², ground-floor security panels, and balcony-level doors. The laminated outer pane adds post-breakage safety and reduces the risk of spontaneous thermal fracture in large panels with high solar absorption. Check panel weight against roller ratings before specifying on panels above 6 m².
For noise-critical rooms within 200 m of an MRT line, expressway, or flight path. The PVB interlayer adds damping that disproportionately attenuates mid-frequency traffic and rail noise. This configuration is available in the TY150 profile and delivers Rw 38–42 dB — sufficient to achieve sleep-quality quiet in most Singapore urban locations.
A practical allocation strategy for a typical 3-bedroom unit: specify the premium laminated configuration for the master bedroom slider and any ground-floor access panel; mid-range argon double-silver for all west and south-facing living area sliders; standard LOW-E argon for east and north-facing bedroom windows. This hierarchy captures 80% of the performance benefit at 65–70% of the cost of uniform premium specification.
IGU Configurations by EZZO Sliding Door Model
TY150 — The High-Performance Sliding Door
The TY150 is EZZO.SG's flagship sliding door profile. Its 150 mm frame width and 5.0 mm wall thickness create a deep rebate that accommodates the widest IGU range in the lineup — including the 5+27A+5mm unit that represents the thermal and acoustic ceiling of standard two-pane assemblies, and optionally triple-pane laminated configurations for the most demanding applications.
The TY150 is designed for large openings — its maximum panel height of 7 m makes it the correct choice for high-ceilinged modern landed properties, penthouse units, and large commercial-residential mixed spaces. At these scales, the glass contribution to heat and noise load is enormous, and under-specifying the IGU creates proportionally larger problems. Recommended standard specification: 5+27A+5mm with argon fill and double-silver LOW-E on west-facing elevations; 5+20A+5mm with standard LOW-E on other orientations. Where ground-floor or balcony security is required, specify laminated outer pane with PVB interlayer across all panels on that elevation regardless of orientation.
TY120 — Standard Residential Sliding Door
The TY120 covers the most common residential sliding door application in Singapore: openings up to 4 m height, standard 2.4 m panel widths, and two-panel or three-panel track configurations. Its 120 mm frame depth permits a maximum of 5+20A+5mm (30 mm total), which is sufficient for excellent thermal and acoustic performance when paired with the right coatings.
The TY120 offers a notable option: a premium LOW-E configuration accommodating a 5+15A+5mm unit (25 mm total). This narrower-cavity configuration exists to reduce panel weight on larger panels — at 2.4 m × 2.4 m, the 5 mm cavity reduction saves approximately 8 kg per panel. The trade-off is a slightly narrower acoustic cavity and marginally higher U-value. For projects where panel weight is already at the roller limit, this is a practical solution; for thermally or acoustically demanding elevations, specify the full 5+20A+5mm and confirm roller capacity instead.
E127 / E190 — Economy and Wide-Frame Options
The E127 and E190 share the same 4.0 mm wall thickness and accept a maximum of 5+20A+5mm (30 mm). The distinction is frame width: the E127's 127 mm frame suits standard residential and light commercial openings; the E190's 190 mm frame provides additional structural span for wider-opening applications. Both accept the same IGU specification. For most residential E-series installations, argon-filled 5+20A+5mm with single-silver LOW-E is the optimal specification — maximising the thermal performance envelope without incurring the cost premium of double-silver on a budget-range profile.
IGU Configurations by EZZO Sliding Window Model
Sliding Window 130 — Side-Press Aluminium
The Sliding Window 130 is EZZO.SG's premium sliding window, featuring side-press sealing, a triple-seal system rated to 700 Pa wind pressure, and an integrated rolling screen. Its 130 mm frame accepts up to 5+20A+5mm (30 mm), making it the only sliding window model in the lineup that matches the thermal capacity of the mid-range sliding door profiles.
The 700 Pa pressure rating is significant: this window can be specified on high-rise facades where wind loads are elevated, and the tight perimeter seal ensures that acoustic performance is limited by the glass rather than by air leakage around the frame — a common failure point in lower-rated windows. Specify argon fill with double-silver LOW-E as standard; the premium sealing system makes this window a genuine high-performance envelope element rather than a commodity product.
Sliding Window 123 — Broken Bridge Thermal
The Sliding Window 123 features a PA66 Nylon thermal-break profile and frame-encased panel construction. Its 123 mm frame with 2.0 mm walls accepts up to 5+15A+5mm (25 mm). This is EZZO.SG's best thermally insulated sliding window due to the PA66 thermal break interrupting the conductive aluminium path through the frame — a significant advantage over non-thermal-break profiles in air-conditioned spaces.
The 5+15A+5mm maximum IGU means that solar and acoustic performance relies more heavily on coating specification than cavity width. Specify double-silver LOW-E with argon fill to compensate for the narrower cavity on west-facing elevations. The thermal-break frame means the overall thermal assembly (frame + glass) can match or outperform a wider-cavity unit in a non-thermal-break frame, because the frame heat path is eliminated.
Sliding Window 112 — Standard Aluminium
The Sliding Window 112 is the entry-level sliding window, with a 112 mm frame, 1.4 mm walls, and a maximum IGU specification of 5+12A+5mm (22 mm total). The narrow 12 mm cavity is the key constraint: this unit provides meaningful improvement over single glazing (Rw approximately 28–30 dB; SHGC reduced by roughly 40% with LOW-E), but cannot match the thermal or acoustic performance of wider-cavity units.
The 112 is appropriate where budget is the primary constraint and the opening is not on a high solar or noise load elevation — for example, internal corridor windows, north-facing study windows, or secondary bedrooms in quiet residential areas. Do not specify this model for west-facing living room openings, rooms within 150 m of major transport infrastructure, or any opening that serves as a primary natural ventilation source in an un-air-conditioned space.
Common Mistakes When Specifying Sliding-System Glass
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Specifying single glazing to save cost
The cost saving on glass is real but small relative to total project cost. The energy cost is permanent and large. A 4 m² west-facing sliding door with single glazing adds approximately SGD 35–55 per month to your air-conditioning bill year-round versus an equivalent LOW-E IGU. Over five years, the energy premium dwarfs any glass savings. This is always a false economy in Singapore's climate.
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Over-specifying acoustic glass where LOW-E suffices
Acoustic laminated configurations cost 40–60% more than standard LOW-E IGU. Specifying them for a bedroom 500 m from the nearest expressway — where the problem is solar gain, not noise — wastes that premium. Solve the right problem at each elevation. The 5-step framework below helps allocate acoustic glass spending to the openings where it actually changes quality of life.
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Forgetting laminated outer pane on ground-floor sliders
Standard tempered glass shatters safely into small fragments — but it does still shatter, and it shatters instantly when struck. A laminated outer pane holds in place after fracture, eliminating the immediate entry route. Ground-floor sliding doors are statistically the primary forced-entry point in Singapore residential burglaries. Laminated glass is not a premium upgrade at ground level; it is a baseline security measure.
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Wrong glass for balcony and pool areas
Sliding doors serving balconies — particularly those with low thresholds or used by children — must use tempered laminated glass on both panes. In pool-facing installations, the glass surface is exposed to high UV, chemical splashback (chlorine), and thermal cycling from water contact. Standard tempered-only glass has a higher rate of spontaneous thermal fracture in these conditions. Specify tempered + laminated as minimum for all pool-level and balcony-barrier sliding doors.
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Ignoring condensation risk from non-thermal-break profiles
Specifying a premium IGU in a non-thermal-break aluminium frame creates a mismatch: the glass performs well thermally, but the aluminium frame conducts cold to the interior face, where condensation forms along the perimeter. This condensation runs into the sill channel, promotes mould, and in timber-reveal installations causes slow wood rot. If you are upgrading to high-performance IGU, pair it with a thermal-break frame. The Sliding Window 123 (broken bridge) is the correct choice for thermally demanding applications in the window lineup.
A Simple 5-Step Decision Framework
Glazing specifications become complicated because multiple variables interact simultaneously. The following framework reduces that complexity to a linear decision path that works for any EZZO.SG sliding system. Work through each step in order — do not skip step 2 regardless of how clear your performance requirements seem.
Is the dominant problem heat (west/south facing, large area), noise (MRT, expressway, flight path), privacy (street-level, overlooked), or security (ground floor, balcony)? Name one primary driver. This determines which glass property you are optimising — SHGC, Rw, VLT, or impact resistance. Secondary needs come in Step 4.
Identify your EZZO.SG sliding door or window model and read the maximum IGU thickness from the profile compatibility table. This is a hard constraint — performance aspirations that exceed it require a profile change, not a glass change. Everything in Steps 3–5 must stay within this limit.
Multiply panel height × width in metres to get area. Then: area × total IGU thickness (mm) × 2.5 kg/m²/mm = glass mass. Add estimated frame weight. Compare against the roller and track weight rating for your profile. If you are over 85% of rated capacity, consider a thinner IGU or a hardware upgrade before proceeding.
With your primary driver and profile limit confirmed, add secondary requirements on top. If noise is secondary, add argon fill and check whether cavity width provides adequate Rw. If security is secondary, add laminated outer pane and recheck panel weight. Each layer adds cost and mass — balance against budget and roller limits.
Submit your panel dimensions, IGU specification, and installation context (floor level, orientation, noise environment) to EZZO.SG's technical team. Validation confirms roller and track compatibility, identifies any edge conditions (e.g., multi-point lock interaction with large panels), and locks the specification for production. This step takes one business day and is provided at no charge.
Ready to Specify Your Sliding System Glass?
Choosing the right IGU for a sliding door or window is a more constrained decision than for casement systems — but it is also a more tractable one, once you understand the profile depth and weight limits. The compatibility table above gives you the hard envelope for every current EZZO.SG sliding model. The budget tiers translate that envelope into practical recommendations by application. And the 5-step framework turns those recommendations into a repeatable specification process that works for any project.
If you are uncertain at any step — particularly around panel weight and roller capacity for large panels — that is exactly what the engineering validation in Step 5 resolves. Our technical team at EZZO.SG reviews sliding system glass specifications as part of the standard project consultation, at no cost to you. Contact us at admin@ezzogenics.com or reach our technical director David directly at david@ezzogenics.com. We are also available in person at Bartley Biz Centre, Blk 15 Kaki Bukit Rd 4, #01-44, Singapore 417808.