When it comes to HVAC systems, ducts are often overlooked, yet they are the backbone of air distribution. Without properly designed and durable ductwork, even the most advanced cooling or ventilation system cannot perform at its best. One of the most important decisions in ductwork design is choosing the right duct material.
Two of the most common options are Galvanized Iron (GI) ducts and Stainless Steel ducts. Each comes with its own advantages, limitations, and ideal applications. While GI is widely used for commercial spaces due to its affordability, stainless steel is preferred in critical facilities where hygiene, safety, and long-term durability are essential.
What Are GI and Stainless Steel Ducts?
Galvanized Iron (GI) Ducts
- GI ducts are manufactured from mild steel sheets coated with zinc.
- The zinc coating helps resist rust for several years.
- They are lightweight, easy to fabricate, and cost-effective.
- Commonly used in malls, offices, warehouses, and standard industrial facilities.
- The biggest advantage is low upfront cost and wide availability.
Stainless Steel Ducts
- Made from alloy steel containing chromium, which forms a protective oxide layer against corrosion.
- Extremely durable and hygienic, making them suitable for sensitive environments.
- Preferred in hospitals, food processing units, pharmaceutical plants, and laboratories.
- The key advantage is long-term reliability with minimal maintenance.
Key Comparison: GI vs. Stainless Steel Ducts
1. Durability & Corrosion Resistance
- GI Ducts: Initially strong, but once the zinc coating wears off, the iron underneath corrodes quickly. In humid or coastal regions, lifespan may be reduced to less than 10 years.
- Stainless Steel Ducts: Naturally corrosion-resistant. Even after decades, stainless steel maintains structural integrity, making it ideal for moisture-rich or chemical-heavy environments.
2. Strength & Performance
- GI Ducts: Adequate for standard airflow systems but may deform under high static pressure.
- Stainless Steel Ducts: Withstand high pressures, fluctuating temperatures, and continuous operation without losing shape or efficiency.
3. Maintenance Requirements
- GI Ducts: Require periodic inspections, repainting, or patching. If ignored, rust spreads, reducing efficiency and lifespan.
- Stainless Steel Ducts: Virtually maintenance-free apart from routine cleaning. No repainting or recoating needed.
4. Cost Factor & Lifecycle Analysis
- GI Ducts: Low upfront cost. A 1,000 sq. ft. ducting project with GI may cost 40–50% less initially compared to stainless steel. However, frequent maintenance and early replacement increase long-term expenses.
- Stainless Steel Ducts: Higher upfront investment but lower lifetime cost. A stainless steel duct can last 20–30 years, compared to GI’s 10–15 years in challenging conditions.
5. Fire Resistance & Safety
- GI Ducts: Zinc coating deteriorates in high temperatures, exposing the iron and weakening duct strength.
- Stainless Steel Ducts: Withstand extreme heat longer, making them more suitable for fire-rated ducts and safety-critical applications.
6. Thermal Efficiency
- GI Ducts: Conduct heat more easily, increasing energy losses if not insulated properly.
- Stainless Steel Ducts: Better thermal resistance and work well with insulation materials to minimize losses.
7. Installation & Fabrication
- GI Ducts: Easy to fabricate, bend, cut, and install. Contractors are more familiar with GI, reducing labor costs.
- Stainless Steel Ducts: Heavier, harder to cut or weld, requiring skilled labor and specialized tools. Installation time may be longer.
8. Environmental Impact
- GI Ducts: Shorter lifespan means more frequent replacements and higher material waste.
- Stainless Steel Ducts: 100% recyclable and longer-lasting, reducing overall environmental impact.
Global Industry Trends
- In India and Southeast Asia, GI ducts dominate due to cost sensitivity, especially in malls and office spaces.
- In developed countries like the US and Europe, stainless steel ducts are increasingly used in critical industries due to stricter regulations on hygiene and sustainability.
- The Middle East prefers stainless steel in coastal cities where humidity and salt air reduce GI duct lifespan significantly.
Which One Should You Choose?
The decision depends on application, budget, and environment.
Choose GI Ducts if:
– You are working on a budget-conscious project.
– The environment is low-risk (dry, non-corrosive).
– Installation speed is a priority.
Choose Stainless Steel Ducts if:
– Hygiene and safety are top priorities (healthcare, food, pharma).
– The environment is humid, coastal, or chemically active.
– You want long-term savings with minimal maintenance.
Degree Day Expertise: Central India’s Leading HVAC Manufacturer
For over 25 years, Degree Day Pvt. Ltd. has been shaping the HVAC industry with energy-efficient, durable, and high-performance solutions. Founded in 2000, Degree Day has grown to become Central India’s largest HVAC manufacturer. Our state-of-the-art manufacturing unit in Indore is equipped with modern machinery for large-scale production. We deliver PAN India, catering to projects ranging from commercial malls and factories to critical healthcare and pharmaceutical environments. Beyond ducts, we offer a comprehensive HVAC product range:
1. Industrial & residential air coolers
2. Air Handling Units (AHU)
3. Medical Grade Air Purifiers
4. Single/Dual Stage Evaporative Coolers
5. Bladeless Fans for modern comfort
With two decades of expertise, our solutions are trusted for quality, reliability, and efficiency, making us a preferred partner for contractors, consultants, and industries across India.
Both Galvanized Iron (GI) ducts and Stainless Steel ducts play a significant role in HVAC system design.
– GI ducts are budget-friendly and easy to install, making them the go-to choice for malls, offices, and warehouses.
– Stainless steel ducts are the premium choice, delivering unmatched durability, hygiene, and safety for critical environments like hospitals, cleanrooms, and food industries.
At Degree Day Pvt. Ltd., we understand that every project is unique. With over 25 years of experience, in-house manufacturing, and a wide product portfolio, we guide clients in selecting the right ducting and HVAC solutions to maximize performance and long-term value.
Whether you need cost-effective GI ducts for a commercial project or stainless steel ducts for a healthcare facility, Degree Day delivers quality you can trust – PAN India.