Steel vs Aluminium Windows : What You Need To Know

• June 3, 2025
• General

When it comes to selecting windows for your home or commercial project, the choice between steel and aluminium can significantly impact aesthetics, performance, and budget.

At Lightfoot Windows, our team has decades of experience in installing steel and aluminium window systems, and we’re here to help. Whether you’re an architect, developer or homeowner, we have the expertise needed to help you make an informed decision.

This guide will help you understand the key differences between these popular window materials and determine which might be the better choice for your specific requirements.

Steel vs aluminium windows: which is best?

Both steel and aluminium windows offer sleek profiles and contemporary styling, but they differ considerably in terms of properties, performance, and price. Whether you’re renovating a period property or designing a modern space, understanding these distinctions is essential for making an informed decision that balances appearance, functionality, and long-term value.

At a glance: the benefits of steel and aluminium systems

Both materials offer significant advantages over alternatives like uPVC.

The unmatched tensile strength of steel allows for the slimmest possible sightlines while maintaining exceptional durability and longevity (often lasting 60+ years with proper care). The inherent strength of steel also provides superior security and excellent fire resistance. Stylistically, the timeless aesthetic of steel windows suits both period and contemporary properties. Steel windows are also hot-dipped galvanised prior to being powder coated, meaning that they offer excellent corrosion resistance.

Aluminium windows also provide corrosion resistance, which is particularly important in coastal areas. Lightweight yet strong, aluminium places less stress on building structures while remaining virtually maintenance-free and requiring only occasional cleaning. Aluminium is highly recyclable, giving it excellent sustainability credentials. A cost effective solution that doesn’t compromise on quality, aluminium also allows for versatile design possibilities.

Both materials allow for generous glazed areas that maximise the amount of natural light entering your property, creating brighter, more inviting spaces.

Cost differences

One of the first considerations for most projects is budget, and there’s a notable difference between steel and aluminium when it comes to initial investment.

Steel windows generally command a higher price point, reflecting their premium status, exceptional strength, and handcrafted nature. The manufacturing process for authentic Crittall steel windows involves skilled craftsmanship, which contributes to their cost.

Aluminium windows are typically more affordable than steel. Aluminium frames offer excellent value without compromising on quality or appearance. The lower cost stems partly from the nature of aluminium and its more straightforward production methods.

Are steel windows more expensive than aluminium?

While steel windows may require a larger upfront investment, their exceptional longevity often results in better long-term value. Aluminium systems present a more budget-friendly option without sacrificing too much in terms of performance or aesthetics, particularly with our Alitherm Heritage profiles.

Thermal efficiency

With rising energy costs and current building regulations focusing on sustainability, thermal performance plays a crucial role in window selection.

Modern steel windows like our Crittall W20 TE range incorporate advanced technology to minimise heat transfer. While traditional steel has historically had lower thermal insulation properties, contemporary steel frames now offer impressive energy efficiency that meets or exceeds building standards. The W20 TE range not only achieves a U-value as low as 1.4 W/m² K but also achieves a thermal gradient across the profile equivalent to that of a thermally broken steel section.

Aluminium window frames would normally conduct heat, but modern aluminium windows feature sophisticated thermal break technology that dramatically improves their insulation capabilities. Our aluminium casement windows deliver excellent thermal efficiency, helping to maintain comfortable indoor temperatures even in cold temperatures.

Both materials can achieve impressive energy performance ratings when properly designed and installed, helping homeowners reduce heating costs while maintaining comfortable indoor environments.

Customisation options for steel vs aluminium windows

The ability to personalise your windows to complement your property’s character is essential.

Steel windows offer timeless elegance with distinctive slim sightlines that cannot be truly replicated. Steel frames can be finished in virtually any RAL colour to suit traditional or contemporary aesthetics, including the iconic black finish that defines the industrial look of genuine Crittall windows.

Aluminium windows are highly versatile in terms of design and colour options. Our aluminium frames can be powder-coated in an extensive range of finishes, including popular anthracite grey and classic white. Modern aluminium systems can be crafted to mimic the appearance of traditional sash windows and other period styles.

Both materials offer excellent opportunities for customisation in terms of style of glazing, hardware options, and configurations, allowing you to achieve the precise look and functionality you desire.

Which is better for my project?

The ideal material depends largely on your specific project requirements:

Consider steel if:

• You desire the distinctive, slim sightlines that only steel can provide
• Maximum strength and security are top priorities
• You’re working on a conservation property where steel replacement windows would be historically appropriate
• You appreciate the unique style of genuine Crittall windows

Consider aluminium if:

• Cost-effectiveness is important without compromising quality
• You require excellent thermal performance
• Lightweight frames would benefit your building’s structure
• Minimal maintenance is desired
• You want a wide range of standard colour options

Why choose Lightfoot windows for your project?

As a premier UK Crittall windows supplier with decades of expertise in both steel and aluminium systems, Lightfoot Windows offers unparalleled knowledge and craftsmanship. Our specialist status within the Crittall network means we provide authentic products installed to the highest standards. We also offer:

• Expert guidance to help you select the perfect material for your needs
• Showroom displaying both steel and aluminium options
• FENSA-accredited installers

We understand that choosing between steel and aluminium involves balancing aesthetics, performance, and budget. Our consultative approach ensures you receive honest, informed advice tailored to your project’s requirements.

Premium solutions for your next project: contact Lightfoot Windows today

Whether you’re leaning towards the timeless elegance of steel or the modern versatility of aluminium, Lightfoot Windows is here to help you make the right choice for your home or project.

Contact us today to discuss your requirements with our friendly experts. Complete our online contact form, call 020 8662 9090, or email general@lightfootwindows.co.uk.

Want to get a quick estimate on new Crittall windows? Simply visit our ‘Get An Estimate’ page and fill out the required information and one of our friendly experts will get back to you within 48 hours.