PRE-INSULATED DUCT vs G.I. DUCTWOK
Pre-insulated duct (typically PIR foam core with aluminum facings) and G.I (Galvanized Iron) duct represent two distinct approaches to HVAC air distribution, differing fundamentally in design, performance, and suitability for project needs. Below is a concise, comparative analysis focused on key metrics for practical decision-making:
Pre-Insulated Duct: An integrated sandwich structure of rigid closed-cell PIR foam (thermal insulation core) bonded to protective facings (aluminum sheet/foil, black aluminum foil, etc.), factory-manufactured for direct installation with built-in insulation.
G.I Duct: Traditional metal ductwork made from galvanized iron sheets, requiring on-site addition of separate insulation materials (fiberglass, mineral wool) to meet thermal efficiency requirements.
| Metric | 20mm PIR Pre-Insulated Duct (with 0.08mm Alu. Foil, ) |
0.5mm G.I Duct + 30mm Rubber Plastic (40-90kg/m3) |
| Fire Safety | Compliant (Class 0/BS 476, AS 1530.3). Self-extinguishing PIR core, low toxic smoke, non-combustible alu foil. | G.I non-combustible; rubber plastic fire-retardant but requires coating to meet strict codes. |
| Thermal Insulation | Excellent. λ=0.022 W/m·K, no thermal bridging. 20mm integrated structure ensures consistent insulation. |
Fair. λ=0.035 W/m·K, thermal bridging at G.I joints. 30mm insulation offset by metal conductivity. |
| Hygiene & Air Quality | Superior. Non-porous alu foil, smooth inner surface, moisture-resistant PIR. Meets cleanroom/hospital standards. |
Poor. Porous rubber plastic traps dust/mold; G.I-insulation gaps breed pathogens. |
| Lightweight | 1.4-1.5 kg/m². Ultra-light, reduces structural load; ideal for retrofits/timber-framed buildings. |
5.1–6.3 kg/m². Heavy G.I base + bulk insulation; requires reinforced supports. |
| Energy Efficiency | Excellent. 20–30% lower HVAC energy consumption. Minimizes heat gain/loss in conditioned air. |
Low. 20–30% higher energy loss due to inferior insulation and thermal bridging. |
| Ease of Construction | Easy. Factory-prefabricated tongue-and-groove joints. No separate insulation step; 40–60% less labor time. |
Complex. Two-step on-site process: G.I duct fabrication + rubber plastic wrapping. Labor-intensive, prone to gaps. |
| Quiet Operation | Good. PIR core absorbs 10–15 dB airflow noise; alu foil dampens vibration. |
Fair. Rubber plastic provides basic sound reduction, but G.I vibration and insulation gaps reduce efficiency. |
| Space Savings | Excellent. 20mm total thickness (all-in-one). Fits tight ceilings/retrofit cavities. |
Poor. 30.5mm total thickness (0.5mm G.I + 30mm insulation). Bulky, requires larger installation space. |
| Environmental Friendliness | Balanced. CFC/HCFC-free PIR, recyclable alu foil. 20–30-year lifespan; net carbon positive in 1–3 years. |
Low. Rubber plastic non-recyclable; 10–15-year lifespan. Frequent replacement increases waste; higher energy emissions. |
| Low Leakage | Superior. ≤2% air leakage (EN 1507, AS/NZS 3660.1). Airtight factory joints + alu foil vapor barrier. |
Poor. 5–10% air leakage. On-site sealing gaps; separate vapor barrier required. |
