English
Double glazed glass (double glazing / insulated glass units / IGU) – complete guide covering configurations from 5+12A+5 to 10+16A+10. Learn about Low-E coatings, argon fill, tempered & laminated options, U-values, acoustic performance, and pricing. CE / ISO 9001 certified. Request FOB quote from Jumbo Glass Group.
Double Glazed Glass / Double Glazing | Insulated Glass Units (IGU) for Windows, Curtain Walls & Facades
Insulated Glass Units (IGU) – The Complete Guide for Procurement Managers & Architects
Double glazed glass (also called double glazing, insulated glass, or IGU) is a factory‑sealed assembly of two glass panes separated by a spacer bar and hermetically sealed to create a single unit with an air‑ or gas‑filled cavity. It is the global standard for energy‑efficient windows, curtain walls, and building facades — reducing heat loss, controlling solar heat gain, minimizing condensation, and improving acoustic comfort.
Whether you are specifying windows for a residential tower, a curtain wall for a commercial high‑rise, or a blast‑resistant facade for a government building, understanding the full range of double glazing configurations is essential to making the right procurement decision.
This guide covers everything a purchasing manager needs to know — from basic terminology to advanced performance data — and explains how to choose the optimal IGU for your project.
A double glazed unit (DGU) consists of:
| Benefit | Description | Impact on Building |
|---|---|---|
| Thermal Insulation | Reduces heat transfer through windows | Lower heating/cooling costs; improved occupant comfort |
| Solar Control | Low‑E coatings and tinted/reflective glass reduce solar heat gain | Reduced air‑conditioning load; glare reduction |
| Acoustic Insulation | Sealed cavity and laminated glass dampen sound transmission | Quieter interiors, especially near roads/airports |
| Condensation Resistance | Inner pane stays warmer, reducing interior condensation | Healthier indoor environment; no mold growth |
| UV Protection | Glass and coatings block >90% of UV radiation | Protects furnishings, artwork, and merchandise from fading |
| Safety & Security | Tempered or laminated panes resist impact and forced entry | Enhanced occupant safety; blast resistance |
| Energy Code Compliance | Meets ASHRAE 90.1, Title 24, EPBD, Green Mark | Facilitates building permit approval |
The industry identifies DGUs by their glass thickness + gap width + glass thickness. For example, 5+12A+5 means 5mm glass + 12mm air gap + 5mm glass.
| Configuration | Total Thickness | Typical Application |
|---|---|---|
| 4+12A+4 | 20mm | Light residential windows (budget) |
| 5+12A+5 | 22mm | Most common residential & light commercial |
| 6+12A+6 | 24mm | Commercial curtain walls, mid‑rise buildings |
| 6+16A+6 | 28mm | High‑performance curtain walls, energy‑code strict |
| 8+12A+8 | 28mm | High‑rise curtain walls, structural glazing |
| 8+16A+8 | 32mm | Hurricane zones, acoustic upgrades |
| 10+12A+10 | 32mm | Mega‑structures, blast‑resistant facades |
| 10+16A+10 | 36mm | Super‑tall towers, Passive House extreme Each configuration can be customized with different glass types, coatings, spacer types, and gas fills. |
| Glass Type | Key Feature | Best For |
|---|---|---|
| Clear Float | Highest light transmission (~82%) | Budget projects, standard residential |
| Low‑E (Single/Double/Triple Silver) | Reflects infrared heat while transmitting visible light | Energy efficiency, LEED projects |
| Tempered (Toughened) | 4–5× stronger than annealed glass; breaks into small cubes | Safety glazing, doors, curtain walls |
| Laminated (PVB or SGP) | Two glass layers bonded with plastic interlayer | Acoustic insulation, security, blast resistance |
| Tinted (Body‑Tinted) | Absorbs solar heat; comes in grey, bronze, green, blue | Solar control, aesthetics |
| Reflective (Online Hard‑Coat) | Mirrored appearance; reflects solar radiation | Privacy, solar control, modern facades |
| Low‑Iron | Ultra‑clear, no greenish tint | Display windows, museums, aquariums |
| Spacer Type | Material | U‑Value Impact | Condensation Risk | Cost |
|---|---|---|---|---|
| Aluminum | Extruded aluminum | Baseline (thermal bridge) | Moderate | Lowest |
| Warm Edge (TPE) | Thermoplastic elastomer | Improves U‑value by ~0.15 | Low | +10–15% |
| Swisspacer | Reinforced polymer | Improves U‑value by ~0.20 | Very low | +20–30% |
| Stainless Steel | Box‑section stainless | Moderate improvement | Low | +15–20% For energy‑code projects, warm edge spacers are now the industry standard. |
| Gas Fill | Thermal Improvement vs. Air | Cost Impact | Best For |
|---|---|---|---|
| Air | Baseline | None | Mild climates, budget |
| Argon | ~15% better U‑value | Low (+$1–2/m²) | Best ROI – most common upgrade |
| Krypton | ~25% better U‑value | Moderate (+$5–8/m²) | Thin gaps, high performance |
| Xenon | ~30% better U‑value | High (+$15–25/m²) | Specialty applications |
Low‑E (low emissivity) coatings are microscopically thin metal oxide layers applied to glass surfaces. They reflect long‑wave infrared heat back into the building while allowing short‑wave visible light to pass through.
| Coating Type | Number of Metal Layers | Typical U‑Value (with Argon) | Best For |
|---|---|---|---|
| Single Silver | 1 | ~1.8 W/m²K | Budget energy efficiency |
| Double Silver | 2 | ~1.5 W/m²K | Most popular – commercial standard |
| Triple Silver | 3 | ~1.2 W/m²K | Passive House, net‑zero buildings Coating placement matters: |
| Configuration | U‑Value (W/m²K) | SHGC | VLT | Rw (dB) |
|---|---|---|---|---|
| Clear / Air | ~2.6 | ~0.76 | ~80% | ~31 |
| Single Silver Low‑E / Argon | ~1.8 | ~0.66 | ~73% | ~31 |
| Double Silver Low‑E / Argon | ~1.5 | ~0.64 | ~70% | ~31 |
| Triple Silver Low‑E / Krypton | ~1.2 | ~0.58 | ~68% | ~31 |
| Laminated (PVB) / Clear / Air | ~2.6 | ~0.74 | ~78% | ~37 Actual values vary with glass thickness, spacer type, and manufacturer. |
Follow this decision tree based on your project priorities:
| Application | Recommended Configuration | Key Considerations |
|---|---|---|
| Residential Windows | 5+12A+5 Low‑E / Argon | Cost‑effective, good thermal performance |
| Curtain Walls – Commercial | 6+12A+6 Double Silver / Argon | Balance of performance and cost |
| Curtain Walls – High‑Rise | 8+12A+8 Double Silver / Argon | Structural strength, wind load |
| Hurricane / Typhoon Zones | 8+16A+8 Tempered / Tempered | Impact resistance, cyclic pressure |
| Blast‑Resistant Facades | 10+12A+10 SGP / SGP | GSA Level C/D, CPNI |
| Hot Climates (Middle East) | 6+12A+6 Reflective / Low‑E | Solar control + thermal insulation |
| Cold Climates (Nordic) | 6+16A+6 Triple Silver / Krypton | Passive House, low U‑value |
| Acoustic Sensitive (Hotels) | 6+12A+6 Laminated / Clear | Rw > 35 dB |
Prices vary significantly by configuration, glass type, and processing. Below are indicative ranges for common double glazed units:
| Configuration | Glass Combination | Gas Fill | FOB Range (USD/m²) |
|---|---|---|---|
| 5+12A+5 | Clear / Clear | Air | $18–28 |
| 5+12A+5 | Low‑E / Clear | Argon | $24–36 |
| 6+12A+6 | Clear / Clear | Air | $20–30 |
| 6+12A+6 | Low‑E (DS) / Clear | Argon | $26–38 |
| 6+16A+6 | Low‑E (TS) / Clear | Krypton | $34–48 |
| 8+12A+8 | Tempered / Tempered | Air | $34–48 |
| 8+16A+8 | Laminated / Laminated (PVB) | Argon | $44–60 |
| 10+12A+10 | SGP Laminated / SGP Laminated | Argon | $78–102 |
💡 For a precise project quotation, send us your glass schedule with dimensions and specifications.
| Standard | Region | Scope |
|---|---|---|
| EN 1279 | Europe | Product standard for IGU |
| CE Marking | Europe | Mandatory for EU |
| ISO 9001 | International | Quality management |
| CCC | China | Mandatory for Chinese market |
| SGS | Global | Third‑party inspection |
| IGCC | USA/Canada | IGU certification |
| ASTM E2190 | USA | IGU performance |
| ASTM E1886/E1996 | USA | Hurricane impact |
| ASTM F1642 | USA | Blast resistance |
| GSA Security Criteria | USA | Blast levels A–D |
Q1: What is the difference between double glazing and triple glazing?
Double glazing has two panes; triple glazing has three. Triple glazing achieves lower U‑values (down to 0.7 W/m²K) but is heavier and more expensive. Double glazing is sufficient for most climates and building codes.
Q2: What does “5+12A+5” mean?
5mm glass + 12mm air gap + 5mm glass. Total thickness = 22mm.
Q3: How long does a double glazed unit last?
Properly manufactured IGUs last 20–30 years. Seal failure is the main cause of replacement.
Q4: Can double glazing be repaired?
No. Once the seal fails, the entire unit must be replaced.
Q5: What is the best configuration for energy efficiency?
For most projects: 6+16A+6 with Double Silver Low‑E on #2 surface, argon fill, and warm edge spacer. This achieves U‑value ~1.4 W/m²K.
Q6: Do you provide samples?
Yes. Free samples (300×300mm) available; customer covers courier.
Q7: What is the lead time?
2–4 weeks for standard configurations; 4–6 weeks for blast/hurricane rated.
Tell us your project requirements and we'll respond within 48 hours with a competitive FOB quotation.
Please provide:
•5+9A+5 / 5+12A+5 Insulated Glass – 20mm & 22mm IGU for residential & light commercial
•6+12A+6/6+16A+6 Insulated Glass–24mm/28mm IGU for heavier duty applications
•8+12A+8/8+16A+8 Insulated Glass – 28mm/32mm heavy‑duty IGU
•10+12A+10/10+16A+10 Insulated Glass – 32mm/36mm high‑performance IGU
•Double Glazed Glass – Standard IGU overview
•Triple Glazed Glass – Three‑pane IGU for Passive House
•Low‑E Insulated Glass – Energy‑efficient IGU with Low‑E coating
•Laminated IGU/safety insulated glass – Acoustic & security insulated glass
•Jumbo Insulated Glass – Up to 3300×12000mm oversized IGU
With over 20 years of experience and expertise in glass manufacturing and processing, we are seasoned glass specialists, ready to answer your questions and provide guidance on product selection, installation, and maintenance.
