While aluminum is lighter and cheaper initially, copper is generally preferred for HVAC piping due to its superior corrosion resistance, durability, ease of repair (solderable), and better long-term performance, as aluminum is more prone to leaks and deterioration, especially in humid environments or with certain water chemistries, requiring costly protective coatings and specialized installation.
Key Drawbacks of Aluminum:
• Corrosion: Aluminum forms a protective oxide layer, but it’s fragile and can rapidly corrode (pitting) in humid conditions or where it contacts other metals, leading to leaks.
• Repair Challenges: Aluminum is harder to solder and repair than copper, often requiring expensive, specialized techniques (like inert gas welding) and skilled labor, increasing maintenance costs.
• Durability: More brittle and prone to damage than copper, aluminum coils often need extra protection, making them harder to clean and maintain.
• Galvanic Corrosion: Soldering aluminum to copper can cause galvanic corrosion, a serious issue in water systems, though less common in sealed refrigerant lines.
Advantages of Copper:
• Corrosion Resistance: Excellent inherent resistance to corrosion, providing a longer lifespan.
• Ease of Installation & Repair: Easily joined by soldering (brazing) with common tools, making installation and repairs simpler and more reliable.
• Thermal Efficiency: Highly conductive, transferring heat efficiently, which contributes to better AC performance.
• Long-Term Value: Despite higher upfront costs, its durability and lower maintenance often make it more economical over the life of the unit.
