Information about steel windows

Steel windows are at the top end of the windows market, offering the slimmest lines and some unique styling. Steel windows are designed to last many years and are arguably some of the best and most sustainable. Now more technically advanced, secure, weather-resistant and low-maintenance, you’ll enjoy high-end windows crafted to the highest standards.

Still enjoying traditional craftsmanship, steel windows are rolled, welded, hot-dip galvanised and then coloured with a durable powder-coated finish.

The latest technology and design of steel windows also provide excellent energy efficiency, giving B window energy ratings in accordance with official ratings councils.

Exterior steel windows types and versions explained

crittall style steel windows in a loft apartment

When choosing the most suitable types of steel windows available, the versions and brands vary depending on the installation and the intended use. You’ll also get a different choice when refurbishing, renovating or replacing steel windows, as well as buying brand-new ones. You can get in touch for details of steel windows and doors suppliers near you.

SMW Standard Metal Windows

The SMW range of steel windows is arguably the original metal window available since the late 1800s. This particular window model suits heritage and those buildings with constraints on window replacements.

Originally available single-glazed, but now with double-glazed units for better insulation, SMW windows are probably the closest match today to old metal windows. As a result, the locking systems are more basic, and you won’t get multiple locking points. Weather sealing, while effective, is more basic and in keeping with the classic design of this system.

Steel windows in W20 versions

The W20 collection of steel windows is probably the most familiar and the style most replicated by aluminium versions of the steel style.

The sightlines of these windows are thinner than aluminium steel-look windows and large screens, patio doors with side panels, and single and French doors in original steel typically use W20 with W30 when also needing matching windows.

W30 steel windows

Steel windows in the W30 design are an improved double-glazed version of W20 and ideal for those windows designed with multiple panels through slim bars, horizontal or diamond leaded designs.

W30 is the most modern of the current collection of steel-window types and achieves the B window energy rating required by Building Regulations. The windows are galvanised and coloured with a powder-coated finish, creating long-lasting windows with minimal maintenance.

W40 Steel windows and doors

Choosing W40 steel profiles enhances doors with triple-glazed units and even lower U-Values or thicker double-glazed units up to 32mm deep. Of course, this more flexible glass rebate design also allows the use of enhanced security laminated glass or acoustic glass.

Complementing W40 is a range of similarly styled windows suitable for residential or commercial projects.

W50TB steel windows

W50TB is a steel window system that also has a thermal break. The styling of these windows is similar to W20 but also ideal where projects want contemporary windows and doors in steel but without the classic Crittall® look. The stronger profiles allow for larger opening window casements and doors and are also the go-to steel product for new build projects.

Steel Windows by Crittall

One of the best known brands for steel windows and doors, Crittall products come with a long history, exceptional quality and one of the best window reputations.

The Crittall range is varied but includes the following:

Corporate W20

The classically styled product aluminium steel look tries to replicate, but only the original remains the best for sightlines, styling and the benefits of steel as a material. Crittall Corporate W20 products are designed for exterior use and usually comprise single or double doors with optional side or top panels.

Popular in conservation areas, the elegant lines of this product is one of the best known and perfect for new extensions and door replacements.

Crittall Homelight Plus

Homelight is a very well-known Crittall product and Plus provides all the styling and functional benefits but with improved performance and quality.

Improved thermal performance, colour finishes, low maintenance and with the latest locking systems and weather sealing. Homelight plus provides the timeless look of Crittall steel windows with all the advantages of modern window and glass technology.

Innervision by Crittall

Innervision is the interior glazing system by Crittall available as hinged or sliding doors, fixed screens and even bespoke shapes using curves and angles.

For internal requirements needing a fire-rated product, the Innervision FR range offers up to 30 minutes of protection.

Internal steel doors, windows and screens

steel windows with doors in an apartment kitchen

While the Crittall® products are some of the best known, independent manufacturers have also designed their bespoke versions. The styling of steel interior doors and screens takes inspiration from W20 and SMW versions, which come with the same slim lines and elegant proportions.

As these products are used internally, they can be single-glazed, without weather seals and offer a substantial range of glass and door handles. Fixed screens, hinged or pivoting doors, and sliding doors are all available as internal steel products.

Choose the correct product and supplier; these products are also available with a fire rating.

How to replace steel windows

Several options are available for properties with existing steel windows, including professional refurbishment and improvement.

Projects requiring new steel windows and doors also now have a broad range of brands and products available. Steel remains the luxury window and door product, built to last, aesthetically excellent and with a build quality like no other material.

The key to getting the best result is to work with a specialist steel supplier who is knowledgeable about the products and with a proven track record.

steel-look windows in a new home made by everglade windows trade

Example properties with original metal windows and doors

Art Deco-inspired houses.

steel windows. many will simply rip them out, others will realise their significance to some properties.

Without a doubt, Art Deco properties are all about slim windows. These are the properties that were largely fitted with steel windows, and anyone with a true Art Deco house who insists on keeping all its original charm would insist on slim windows.

Ideally, you would replace your steel windows with an exact copy. However, if budget is important, a specialist window installer can provide credible alternatives to steel.

The traditional 3-bed semi.

the typical british home. shown here totally original and the white pvc in the adjoining property

1930s England is famous for its iconic houses, particularly the semi-detached home with bay windows, three bedrooms and spacious rooms. Many of these came with original metal windows, with the vast majority now replaced with aluminium, PVCu or timber windows.

The W50TB is one of the better solutions for those wanting to replace dated windows with a new steel version.

Steel windows in the Sunshine Bay design.

buying jennyfields steel-look windows
Image courtesy of

Whilst three are some specialist aluminium installers offering sunshine bays, steel windows remain the best product when windows need curving. Original windows feature horizontal window profiles and curved glass.

Several window companies may avoid curved on-plan windows such as sunshine bays, but the steel window specialists should have no problem recreating the original look of the steel windows with a new version.

black powder coated window in hardwood subframe with external crittall bars. typical of country properties and cottages

Steel windows in stone and timber surround

Aluminium windows provide a solution for fitting within existing stone or timber mullions, but steel windows provide the best and slimmest aesthetics. PVCu windows simply destroy the look of the house.