Aluminium: a viable alternative to copper windings?

3 February 2026  

An industrial inductor with aluminium foil windings and copper busbar terminations

As copper prices hit record highs, engineers are reassessing whether aluminium is now a more attractive option for some winding applications. Steve Hughes, managing director of REO UK, examines the pros and cons.

Record-high copper prices are prompting manufacturers in the electrical engineering sector to reassess long-held assumptions about the winding materials they use in electromagnetic components such as transformers, chokes, and inductors. The sharp rise in copper costs – driven by supply shortages, geopolitical constraints and escalating demand from electrification – has made aluminium and hybrid aluminium–copper windings significantly more attractive than before.

Engineers and procurement teams are now confronting a reality in which traditional copper-first design philosophies may no longer be economically sustainable, particularly for large-volume or cost-sensitive applications.

Copper’s material advantages are well understood: excellent conductivity; favourable thermal properties; and strong mechanical resilience. These characteristics have historically justified copper’s higher cost. But with global copper prices reaching unprecedented levels, the economic balance has shifted sharply.

Aluminium – traditionally seen as a secondary or compromise material – is now re-entering conversations at the design stage. Its conductivity, about 60% that of copper, does require larger cross-sections to achieve equivalent performance. In practical terms, this typically means a conductor with roughly 1.6 times the cross-sectional area.

Yet in many designs, especially those where space is not a constraint, this increase is less restrictive than previously assumed.

Engineers are realising that the decision is no longer just about electrical performance – it’s now about the sustainability of raw material costs over the lifespan of a product. The economics of manufacturing relatively large inductive components have changed faster than the technology itself.

Why is aluminium gaining ground?

The renewed interest in aluminium stems from several pragmatic factors:

• Cost stability  Even with the need for increased conductor volumes, aluminium remains much cheaper than copper. With copper prices at record highs, this gap is more pronounced than at any point in the past decade.
• Weight benefits  Aluminium’s lower density makes it especially valuable in applications where total system weight is critical – such as transportation, mobile equipment, and installations where structural loads must be reduced.
• Modern joining techniques  Improved mechanical terminations and surface treatments have addressed many of aluminium’s historical weaknesses, such as oxidation at connection points and concerns over long-term contact reliability.
• Suitability for lower-density designs  For inductors, filters and transformers operating at low to medium frequencies – particularly those with generous coil windows – aluminium’s larger cross-section is rarely a limiting factor.

These considerations are now prompting design engineers to revisit winding specifications that may have gone unchanged for years.

Despite the market pressures, copper’s position in certain high-performance applications remains secure. It is still the preferred choice for:

• high-frequency inductors and chokes;
• compact magnetic components where space is constrained;
• harsh thermal environments;
• precision applications such as medical electronics; and
• high-reliability sectors, such as rail traction and industrial power conversion.

In these cases, copper’s conductivity and mechanical behaviour are difficult to replace without compromising efficiency or reliability. The debate, therefore, is not a simple switch, but a more nuanced design decision based on each product’s operating environment and performance requirements.

As attractive as aluminium has become, there are still applications where copper remains the only option. The challenge for designers is to identify where aluminium is a smart alternative and where copper is still essential.

Hybrid windings

A significant development emerging from the cost debate is the use of hybrid windings. These include copper-terminated aluminium conductors, copper-clad aluminium, or mixed-material winding arrangements that distribute current more efficiently and improve thermal behaviour.

These hybrid approaches combine copper’s connectivity and durability with the economic benefits of aluminium, offering an appealing option for applications that sit between cost-driven and performance-critical design categories.

The spike in copper pricing has quickly become one of the most influential factors in transformer and choke design. While aluminium has always been present in some sectors – such as distribution transformers and large inductors – its adoption in specialised industrial and power-electronics applications is expected to accelerate.

The conversation is now shifting from ‘Why would we use aluminium?’ to ‘Why wouldn’t we consider it?’. The commercial arguments have changed dramatically, and the industry is having to catch up with that reality.

With continued volatility expected in global copper markets, we are likely to see sustained interest in alternative winding materials. The long-term outcome may be a more diversified industry, where copper retains its position in premium performance applications, while aluminium – either alone or in a hybrid form – could become a mainstream option, rather than a fallback.

Engineers, OEMs and specifiers need to revisit their material assumptions with fresh eyes, applying today’s economic realities rather than relying on historical norms.