UPVC Windows — Complete Guide
UPVC (Unplasticised Polyvinyl Chloride) windows are weather-sealed, energy-efficient, thermally insulated, modern fenestration systems built from multi-chambered rigid PVC profiles reinforced with galvanised steel inserts. They have rapidly become the preferred premium window choice in India for residential, commercial and institutional buildings.
UPVC windows are governed by IS 12372 (Method of Tests for UPVC Profiles), IS 15208 (UPVC Profiles for Windows / Doors) and European RAL standards. Top brands: Fenesta (DCM Shriram), LG Hausys, Aluplast (Aparna), Aluplast (German), Veka, Profine, Encraft, Aluplast Aparna, NCL Window, AIS Windows.
What is UPVC?
UPVC stands for Unplasticised PVC — PVC without softening plasticisers, giving it rigidity, weather resistance and longevity. The UPVC profile is extruded with multiple internal air chambers (3 to 8) that provide thermal insulation and structural strength. A galvanised steel insert is added inside main chambers for structural reinforcement.
UPVC windows offer 30–40% better thermal insulation than aluminium, 80% better than single-pane wood, virtually zero maintenance for 25+ years, 100% waterproof rubber gaskets, multi-point locking for security, and beautiful clean modern aesthetics — making them the gold standard for premium fenestration globally.
UPVC Profile Anatomy
- Outer Frame: 60–88 mm wide profile fixed in wall opening
- Sash Frame: Moving / opening profile carrying glass
- Multi-Chamber Construction: 3 / 4 / 5 / 6 / 8 internal air chambers (insulation)
- Steel Reinforcement: 1.2–1.5 mm galvanised steel insert (structural)
- EPDM Gaskets: Rubber seals at glass / frame / sash junctions
- Glazing Bead: Snap-in profile holding glass in place
- Drainage Slots: Water drainage through controlled outlets
- Glass: Single pane (5/6/8 mm) or Double Glazed Unit (DGU)
- Hardware: Multi-point lock, hinges, handles, friction stays
- Mullion / Transom: Internal divider profiles
Types of UPVC Windows
| Type | Opening Style | Use |
|---|
| Casement Window | Hinged, swings open like a door | Living, bedroom (most common) |
| Top-Hung / Awning | Hinged at top, opens outward | Bathrooms, kitchen (rain protection) |
| Bottom-Hung / Hopper | Hinged at bottom, tilts in | Basement, ventilation |
| Sliding Window (2-Track / 3-Track) | Horizontal slide | Standard residential |
| Slide & Fold (Bi-fold) | Folds like accordion | Patio, balcony, expansive openings |
| Lift & Slide | Lifts before sliding (heavy) | Premium patio doors |
| Tilt & Turn | Tilts in (vent) or turns (door) | Premium European-style |
| Tilt & Slide | Tilts for vent, slides to open | Premium balcony |
| Fixed (Picture) Window | Non-opening, large glass | Decorative / view-only |
| Combination Window | Mix of fixed + opening | Living rooms, large openings |
| Bay / Bow Window | Projecting from facade | Premium residential |
| Arched / Curved | Special shape, fixed | Heritage / designer |
Profile Series & Specifications
| Profile Series | Profile Depth | Chambers | Use |
|---|
| 60 mm Series | 60 mm | 3 / 4 chamber | Standard residential |
| 70 mm Series | 70 mm | 5 chamber | Premium residential |
| 76 mm Series | 76 mm | 5 / 6 chamber | Energy-efficient homes |
| 82 mm Series | 82 mm | 6 / 7 chamber | Premium thermal performance |
| 88 mm Series | 88 mm | 7 / 8 chamber | Passive house / cold climate |
Profile Class (per RAL)
| Class | Wall Thickness (Outer) | Use |
|---|
| Class A | > 2.8 mm | Premium, residential / commercial |
| Class B | 2.5 – 2.8 mm | Standard residential |
| Class C | < 2.5 mm | Budget / mass-housing |
Physical Properties (IS 12372)
| Property | UPVC Profile Requirement |
|---|
| Density | 1.40 – 1.45 g/cm³ |
| Vicat Softening Point | > 82°C |
| Charpy Impact (23°C) | > 7 kJ/m² |
| Tensile Strength | > 40 MPa |
| Elongation at Break | > 100% |
| Modulus of Elasticity | > 2400 MPa |
| Heat Reversion | < 2.5% |
| Mass Loss | < 0.4% |
| UV Stability | 4500 hr Xenon arc (no chalking) |
| Linear Thermal Expansion | 7 – 8 × 10⁻⁵ /°C |
| Thermal Conductivity (U-value, profile) | 1.0 – 1.8 W/m²K |
| U-value (Window incl. glass) | 1.3 – 2.5 W/m²K |
| Sound Reduction (Rw) | 30 – 45 dB (depends on glass) |
| Air Permeability | Class 4 (best, < 3 m³/h.m²) |
| Water Tightness | Class 9A (best) |
| Wind Load Resistance | Class A4 / B3 / C2 (varies) |
| Operating Temperature | −20 to +60 °C |
| Lifespan | 25 – 50 years |
Glass / Glazing Options
| Glass Type | U-Value | Use |
|---|
| Single Pane Float (5/6/8 mm) | 5.7 W/m²K | Budget, internal |
| Tinted / Reflective Single | 5.5 W/m²K | Heat reduction |
| Toughened (Tempered) | 5.7 W/m²K | Safety areas, balcony |
| Laminated Glass | 5.5 W/m²K | Security, sound insulation |
| Double Glazed Unit (DGU, 6+12+6) | 2.8 W/m²K | Premium thermal / sound |
| DGU with Argon Fill | 2.4 W/m²K | Energy efficient |
| Low-E DGU | 1.6 – 1.8 W/m²K | Passive house, AC efficient |
| Low-E + Argon DGU | 1.1 – 1.4 W/m²K | Best energy efficiency |
| Triple Glazed (TGU) | 0.6 – 1.0 W/m²K | Extreme climates / passive house |
| Acoustic Laminated | 5.0 W/m²K | Highway / airport zones |
| Smart Glass (Switchable) | Varies | Premium high-tech |
Top Brands in India
- Fenesta (DCM Shriram) — Indian #1 brand, in-house fabrication
- LG Hausys — Korean premium
- Aluplast (Aparna Enterprises) — German technology, Indian assembly
- Veka — German premium profiles
- Profine / Trocal / Kommerling — German premium
- Encraft (Aluplast / NPCS) — Indian assembly
- NCL Window Systems — Indian brand
- AIS Windows (Asahi Glass) — Glass + window combo
- REHAU — German premium
- Schueco — German premium engineering
- Internorm — Austrian premium
- Eternia (Hindalco) — Mix aluminium / UPVC
- UPVC India — Indian brand
- Aparna Windows — Indian fabricator
Hardware Components
Casement Window Hardware
- Multi-point locking mechanism
- Espagnolette handle (turn lever)
- Friction stay / scissor hinge
- Striker plates
- Limiter / restrictor
- Espagnolette gearbox
Sliding Window Hardware
- Tandem rollers (wheels)
- Crescent / hook lock
- Track / runner
- Anti-lift block
- Brush seals / weather strips
- Stainless steel mosquito net (optional)
Tilt & Turn Hardware
- Tilt & turn handle (3-position)
- Multi-point lock with corner drive
- Scissor stay
- Anti-lift mushroom cam locks
- Anti-burglary striker plates
UPVC vs Aluminium vs Wooden Windows
| Parameter | UPVC | Aluminium | Wooden |
|---|
| Thermal Insulation (U-value) | 1.3 – 2.5 W/m²K (excellent) | 3.5 – 6.5 W/m²K (poor, unless thermal break) | 2.0 – 3.0 W/m²K (good) |
| Sound Insulation | 30 – 45 dB | 25 – 35 dB | 25 – 32 dB |
| Water Tightness | Excellent | Good (gaskets fail) | Limited |
| Maintenance | Very Low | Low | High (re-polish, paint) |
| Termite-Proof | Yes | Yes | Risk (treated wood) |
| Corrosion / Rust | None | None (anodised) | NA |
| UV Resistance | Excellent (UV stabilised) | Excellent | Fades |
| Lifespan | 25 – 50 years | 30 – 50 years | 20 – 100 years (Burma teak) |
| Frame Width (visible) | Wider (70–88 mm) | Slim (45–55 mm) | Varies (60–100 mm) |
| Customisation | Limited (factory made) | Good | Excellent (custom carving) |
| Heritage Aesthetic | Modern | Modern | Traditional |
| Cost (Rs/sqft, all-in) | 500 – 1,500 | 250 – 800 | 800 – 3,500+ |
| Best For | Premium, AC homes, noisy areas, coastal | Budget, dry climate | Heritage, traditional |
Standard Sizes & Configurations
| Application | Standard Size (mm) | Configuration |
|---|
| Small Bathroom Window | 600 x 600 / 900 x 600 | Single casement / top hung |
| Kitchen Window | 1200 x 900 / 1500 x 900 | 2-track sliding / casement |
| Bedroom Window | 1500 x 1200 / 1800 x 1200 | 2/3-track sliding / casement |
| Living Room | 2400 x 1500 / 3000 x 1500 | 3/4-track sliding / combination |
| Balcony / French Door | 2100 x 2400 / 2400 x 2400 | Slide & fold / tilt & slide |
| Ventilator (Top Hung) | 900 x 450 / 1200 x 450 | Top hung / louvered |
| Picture / Fixed | Custom (up to 4000 x 2500) | Fixed glazing |
| French Casement | 1200 x 1800 / 1500 x 2100 | Double casement |
Step-by-Step Installation
- Site Measurement: Accurate measurement of wall opening (length x width)
- Order: Custom factory fabrication based on opening + 10–15 mm gap
- Delivery / Quality Check: Inspect for damage, scratches, dimensions
- Wall Preparation: Plaster cured, opening clean, square, plumb
- Frame Insertion: Lift frame into opening
- Levelling: Use packers / wedges to level (top, bottom, sides)
- Plumb Check: Verify with spirit level / laser
- Fixing Anchors: Fix with 75 mm fixing screws / metal frame anchors at 600 mm c/c
- Foam Sealing: Inject expanding PU foam into gap (frame + wall)
- Foam Trimming: Cut excess foam after 1 hr cure
- Sealant: Apply silicone sealant on exterior and interior junctions
- Sash & Hardware: Install sash, hardware (hinges, locks)
- Glazing: Insert glass with EPDM gaskets, snap glazing bead
- Test Operation: Open/close, lock test, water spray test
- Architrave / Trim: Install decorative trim on interior
- Final Cleaning: Remove protective film, clean glass
- Snagging: Final inspection for adjustments
Advantages
- Excellent thermal insulation (saves 20–40% AC costs)
- Superior sound insulation (30–45 dB reduction)
- 100% waterproof (no monsoon leakage)
- Termite, corrosion, rot proof
- UV stabilised (no yellowing for 25+ years)
- Multi-point locking (high security)
- Very low maintenance (just wipe)
- 25–50 year warranty
- Air-tight (zero dust infiltration)
- Available in many colours / wood-grain laminate
- Suitable for coastal / humid / desert climates
- Energy-efficient (LEED / GRIHA points)
- Fire retardant (self-extinguishing UPVC)
- Recyclable (eco-friendly end-of-life)
- Custom shapes possible (arched / round)
- Premium aesthetic (modern clean lines)
- Suitable for cyclone-prone areas (with reinforcement)
- No painting / staining required
- Wide hardware options
- Engineered drainage (no water ingress)
Disadvantages
- Higher initial cost than aluminium (Rs 500–1500 vs Rs 250–800/sqft)
- Wider frame profile (70–88 mm) reduces glass area visually
- Limited factory customisation
- Surface damage difficult to repair
- Wood-grain laminate can fade in tropical sun
- Initial chemical odour (off-gas for 2–4 weeks)
- Quality varies dramatically between brands
- Counterfeit / low-grade profiles common
- Heavy weight in large sizes
- Requires factory fabrication (lead time 2–4 weeks)
- Heat sensitivity in extreme conditions (> 65°C)
- Cannot be hand-modified on site
- Specialised installation required
- Long lead time for repairs
- Limited frame colours (mostly white / brown / wood)
Cost (Approximate, Indian Market — per sqft, all-in)
| Configuration | Cost (Rs / sqft) |
|---|
| 2-Track Sliding with Single 5 mm Glass | 500 – 750 |
| 3-Track Sliding with Single 5 mm Glass | 600 – 900 |
| 2-Track Sliding with DGU | 800 – 1,200 |
| Casement Window with Single 5 mm Glass | 550 – 850 |
| Casement Window with DGU | 900 – 1,400 |
| Casement with Low-E DGU + Argon | 1,300 – 1,900 |
| Top Hung / Awning | 650 – 950 |
| Tilt & Turn Window | 1,100 – 1,700 |
| Slide & Fold (Bi-Fold) Window/Door | 1,500 – 2,500 |
| Lift & Slide Door | 1,800 – 3,200 |
| Fixed Picture Window | 400 – 700 |
| Bay Window (Premium) | 1,500 – 2,800 |
| Add for Mosquito Net (SS, Pleated) | +150 – 300 / sqft |
| Add for Wood-Grain Finish | +15–25% over base |
| Add for Premium Brand (Fenesta / LG) | +25–40% over standard |
Standard Window Costs
| Window Size | 2-Track Sliding (Rs) | Casement (Rs) |
|---|
| 900 x 600 (Small bathroom) | 4,500 – 6,500 | 5,000 – 7,500 |
| 1500 x 900 (Kitchen) | 7,500 – 12,500 | 8,500 – 14,500 |
| 1500 x 1200 (Bedroom) | 10,000 – 17,000 | 11,500 – 19,500 |
| 2400 x 1500 (Living) | 21,000 – 38,000 | 22,500 – 42,000 |
Tests on UPVC Windows (IS 12372)
- Vicat Softening Point Test — IS 12372 Part 2
- Charpy Impact Test (23°C, 0°C, −10°C) — IS 12372 Part 3
- Tensile Strength & Elongation — IS 12372 Part 4
- Heat Reversion / Dimensional Stability — IS 12372 Part 5
- Mass Loss after Heat Aging — IS 12372 Part 6
- UV Weathering — ISO 4892-2 (Xenon arc, 4500 hr)
- Profile Dimensional Tolerance — IS 15208
- Wall Thickness Test — IS 15208
- Welded Corner Joint Strength — EN 514
- Air Permeability — EN 1026 / IS 1948
- Water Tightness — EN 1027
- Wind Load Resistance — EN 12211
- Burglar Resistance — EN 1627 (RC1 to RC6)
- Operational Forces — EN 12046 (handle force)
- Durability of Hardware — EN 12400 (cycles to failure)
- U-value — EN ISO 10077-2
- Sound Insulation Rw — EN ISO 717
Best Practices
- Choose 70 mm or 76 mm profile minimum for premium homes
- Use 5-chamber profile for best thermal performance
- Insist on Class A profile (> 2.8 mm wall thickness)
- Use galvanised steel reinforcement (1.5 mm thick) for windows > 1.5 m
- Use DGU (6+12+6) for noisy / hot climates
- Use Low-E coating for AC homes (saves 30% cooling)
- Insist on EPDM gaskets (not PVC) for waterproofing
- Use stainless steel hardware
- Multi-point locking for security
- Specify Maco / Roto / Siegenia hardware (European premium)
- For sliding, use tandem (4-wheel) rollers (durable)
- Verify Fenesta / LG / Aluplast / Profine origin
- Get water spray test post-installation
- Maintain 10–15 mm gap around frame for foam sealant
- Use polyurethane foam (not silicone) for sealing wall gap
- Apply silicone sealant exterior & interior
- Window should be installed AFTER plaster, BEFORE paint
- Periodic gasket inspection (every 3–5 years)
- Clean hardware annually with light oil
- Manufacturer warranty card (10–25 years)
Applicable Standards
| Standard | Description |
|---|
| IS 12372 | Method of Tests for UPVC Profiles (Parts 1–6) |
| IS 15208 | UPVC Profiles for Doors & Windows — Specification |
| IS 1948 | Aluminium Doors, Windows & Ventilators (related) |
| EN 12608 | UPVC Profiles for Window / Door Manufacture |
| EN 12608-1 | UPVC Profile Classification |
| EN 1026 | Air Permeability Test |
| EN 1027 | Water Tightness Test |
| EN 12211 | Wind Resistance Test |
| EN 12046 | Operating Forces |
| EN 12400 | Mechanical Durability |
| EN 1627 / 1628 / 1629 / 1630 | Burglar Resistance Classes (RC1 to RC6) |
| EN 14351-1 | Window & External Pedestrian Door Standard |
| EN ISO 10077-1 / 2 | Thermal Performance of Windows |
| EN ISO 717-1 | Sound Insulation |
| RAL-GZ 716 | Quality Mark for PVC Window Profiles |
Conclusion
UPVC windows have established themselves as the premium fenestration choice in modern Indian construction. With superior thermal insulation, sound dampening, water tightness, zero maintenance and 25–50 year lifespan, they justify their premium pricing (Rs 500–1500/sqft) through energy savings, comfort, security and aesthetic value.
Recommendations:
- Standard residential: 60–70 mm profile, 2/3-track sliding with 5 mm float glass (Rs 500–900/sqft)
- Premium homes: 76 mm 5-chamber profile, casement with DGU (Rs 900–1400/sqft)
- AC-heavy homes: Low-E DGU for energy efficiency (Rs 1300–1900/sqft)
- Noisy locations (highway / airport): Laminated DGU for sound reduction (45 dB)
- Coastal / humid: UPVC ideal (no corrosion)
- Cyclone-prone: Reinforced UPVC with toughened glass
- Premium balcony / patio: Slide & fold or lift & slide system
- Heritage homes: Use solid teak / wood windows
- Budget constrained: Aluminium sliding instead
Compare with aluminium sliding windows and traditional wood for trade-offs. For doors, see flush doors, WPC / PVC doors, or FRP / steel doors for main entrance.