When designing heat exchangers for HVAC systems, radiators, automotive cooling units, or industrial equipment, material selection is one of the most critical decisions. Among the common choices—aluminum, stainless steel, and copper—copper (also known as "red copper" or pure copper) and brass (a copper-zinc alloy) are two widely used copper-based materials.
But which one performs better in real-world thermal applications? This article compares brass vs. copper in terms of thermal conductivity, corrosion resistance, mechanical strength, manufacturability, and cost, helping engineers and procurement teams make informed decisions.
What Are Brass and Copper?
| Material | Composition | Common Grades |
|---|---|---|
| Copper (Red Copper / Pure Copper) | ≥99.9% Cu | C11000, C12200, ASTM B280 |
| Brass | Cu + Zn (typically 60–70% Cu, 30–40% Zn) | C26000 (Cartridge Brass), C27000, H65 |
Both are non-ferrous metals with excellent electrical and thermal properties, but their performance in heat exchanger applications differs significantly.
Thermal Conductivity – Copper Wins Hands Down
The primary function of a heat exchanger is to transfer heat efficiently. Here, thermal conductivity is king.
| Material | Thermal Conductivity (W/m·K) |
|---|---|
| Pure Copper (C11000) | ~390 |
| Brass (C26000) | ~110–125 |
👉 Copper conducts heat over 3 times more efficiently than brass.
This makes pure copper the ideal choice for high-performance cooling systems where maximum heat transfer efficiency is required — such as in:
- Air conditioning evaporators and condensers
- Precision cooling units
- High-load industrial heat exchangers
✅ Winner: Copper — unmatched thermal performance.
Mechanical Strength & Formability
| Property | Copper | Brass |
|---|---|---|
| Tensile Strength | Moderate (~210 MPa) | Higher (~370 MPa) |
| Hardness | Softer | Harder and more wear-resistant |
| Ductility | Excellent – easy to bend, flare, expand | Good, but less ductile than pure copper |
| Machinability | Lower | Very good (especially free-cutting brass) |
- Brass offers better mechanical strength and wear resistance, making it suitable for parts that require threading or mechanical durability (e.g., fittings, valves, connectors).
- Copper is softer and more ductile, making it ideal for tube bending and flaring without cracking — crucial in complex heat exchanger coil designs.
✅ Copper for tubing, Brass for fittings — the best of both worlds.
Corrosion Resistance – It Depends on the Environment
| Environment | Copper | Brass |
|---|---|---|
| Freshwater | Excellent | Very Good |
| Saltwater / Marine | Good (with inhibitors) | Prone to dezincification |
| High-Chloride Water | At risk of pitting | High risk of corrosion |
| Ammonia or Sulfur Environments | Vulnerable | Even more vulnerable |
- Pure copper has superior general corrosion resistance, especially in soft water and closed-loop systems.
- Brass can suffer from dezincification — where zinc leaches out in aggressive water (especially hot, low-pH, or chlorinated), leaving a weak, porous copper structure.
🔧 Tip: Use inhibited copper tubes or arsenic-doped brass in challenging environments to improve longevity.
✅ Winner: Copper — more reliable in long-term thermal applications.
Cost & Availability
| Factor | Copper | Brass |
|---|---|---|
| Raw Material Cost | Higher (pure Cu price) | Lower (less copper content) |
| Fabrication Cost | Moderate | Often lower due to better machinability |
| Scrap Value | High | Moderate |
- Brass is cheaper due to lower copper content and easier machining.
- However, lower upfront cost may lead to higher lifetime cost if the system suffers from early failure or reduced efficiency.
✅ Brass for budget-sensitive projects, Copper for performance-critical systems.
Compatibility & System Integration
- Both materials can be brazed or soldered using silver-based or phosphorus-copper alloys.
- However, galvanic corrosion may occur if copper and brass components are directly connected in the presence of an electrolyte (e.g., water).
- ✅ Use dielectric unions or insulating sleeves to prevent this.
- In mixed-material systems, use brass fittings with copper tubing — a common and reliable combination.
When to Use Which?
| Application | Recommended Material | Why |
|---|---|---|
| High-efficiency AC condensers | ✅ Copper | Maximizes heat transfer |
| Automotive radiators | ✅ Copper or Copper-Brass combo | Balance of performance and cost |
| Marine heat exchangers | ✅ Copper (with inhibitors) | Resists saltwater corrosion |
| Valves and connectors | ✅ Brass | High strength, good threading |
| Budget cooling units | ✅ Brass tubing | Lower cost, sufficient for low-demand use |
💡 Best Practice: Use copper for heat transfer tubes, and brass for structural or threaded parts.
Conclusion: It’s Not "Either/Or" — It’s About Smart Selection
While pure copper outperforms brass in thermal conductivity and corrosion resistance, brass offers better strength and machinability at a lower cost.
For heat exchanger design, the optimal approach is often hybrid:
- Copper tubes for maximum heat transfer efficiency
- Brass fittings or headers for durability and ease of assembly
At Hailiang, we manufacture high-quality copper and brass tubes for heat exchanger applications, fully compliant with ASTM B280, BS EN 12737, and GB/T 8891 standards. Whether you need soft-annealed copper coils or drawn brass tubes, we can support your engineering and supply needs.
📞 Contact us for technical consultation, material samples, or custom specifications.
