When designing a reliable and cost-effective solar PV system, the choice of mounting structure material plays a crucial role. Two of the most common materials used are aluminum and steel—but which one is better?

This article compares the two from key aspects including durability, weight, corrosion resistance, cost, and application scenarios.

1. Durability and Structural Strength

Steel is generally stronger and better suited for large-scale ground-mounted systems where high wind or snow loads are a concern.

Aluminum, while lighter, still offers adequate strength for rooftop and carport applications, especially with proper design.

Verdict: Steel wins in strength, especially for utility-scale and harsh environments.

2. Weight and Ease of Installation

Aluminum is significantly lighter than steel, making it easier and faster to transport and install—especially on rooftops.

Less weight means less stress on the roof and often lower labor costs.

Verdict: Aluminum offers clear advantages in weight-sensitive installations.

3. Corrosion Resistance

Aluminum naturally resists corrosion without the need for additional coating.

Steel requires galvanization or special coatings (e.g., hot-dip galvanized or Zn-Al-Mg) to withstand corrosion, especially in coastal or humid environments.

Verdict: Aluminum is better suited for corrosive environments such as coastal areas and high humidity zones.

4. Cost

Steel is generally more cost-effective in terms of raw material price.

However, aluminum can reduce total costs by lowering transportation and installation time.

Verdict: Steel may win on material price, but aluminum can reduce overall project cost in the right scenario.

5. Application Suitability

In terms of application suitability, aluminum is recommended for rooftop systems and coastal areas due to its lightweight and corrosion resistance.

For large utility-scale farms, steel is typically preferred thanks to its superior strength.

Carports can use either material depending on the specific design requirements.

In regions with heavy snow or wind loads, steel is generally the better choice.

Conclusion

Both aluminum and steel have their own advantages depending on project type and site conditions.

Aluminum is ideal for lightweight, corrosion-resistant rooftop and residential systems, while steel is often the preferred choice for cost-sensitive, large-scale installations requiring higher structural strength.

If you're looking for a reliable mounting solution provider, UISOLAR offers both aluminum and steel systems that are certified, customizable, and engineered for long-term durability.

With over 15 years of experience and projects in more than 100 countries, UISOLAR is committed to helping you find the right structure for every solar project—from residential rooftops to utility-scale solar farms.