The Steel Window Myth Explained

The Steel Window Myth Explained

Steel windows and doors have been in existence since the 1930’s. A well manufactured window will last, easily, for 50 years or more.

You are still able to find the traditional single glazed steel windows, commonly known within the industry as the SMW window. If you have existing steel windows and live in a listed property or conservation area these are the windows you will normally be required to replace your originals with.



However, not all steel window manufacturers produce the SMW, so it pays to ask at the beginning of your purchase journey if you will be getting the SMW window and not a look alike, which isn’t the same!

There are many different profiles, which are all supplied by one supplier, a company called Montanstahl. They hot roll the steel to form the profiles used by window manufacturers. You will see the likes of W20, W30, W40, W40, W50TB etc used in the UK.

If you specify a Shueco aluminium window system, Shueco will ask one of their fabricators to manufacture and install it for them, as Shueco are the aluminium profile system producer. Montanstahl are the producer of the steel window profile systems.

If you take the number, then the windows or doors you will receive from any manufacture is manufactured from the SAME profile produced by Montanstahl! Some companies have chosen to brand their offering slightly differently to try and say it is a different system, it isn’t!



A lot of people will call steel windows, Crittall Windows, and the reason for this is that Crittall are the largest manufacturer of steel windows and doors. They have a long history having been formed in 1849. During the times of having the choice of either timber or steel windows, Crittall had many factories across the world producing steel windows and doors. So Crittall became the brand leader of its time, and its stuck. It is like Hoover of the vacuum cleaner world! We all talk about doing the hoovering, but if you have a Dyson do you say I’m going to do the Dysoning?

The way steel windows and doors are manufactured should be the same, regardless of the factory they come out of. They should be manufactured to BS6510, powder coated to BS6497 and many will have the same ironmongery on. Suppliers to the steel window market are limited.

The industry is overseen by the Steel Window Association and you really should only purchase (specify) from companies who are members. The question to ask is, if a manufacturer isn’t a member, why not? Are they complying to the above-mentioned standards? What sort of warranty will they offer you, the customer? 

Established in 1943, West Leigh provides highly specialist bespoke steel window services across a wide range of buildings and industries. From Curtain Walling to Heritage and refurbishment projects, our highly skilled team work nationwide on a range of credible projects. Our advanced approach to steel window design, repair and installation makes West Leigh the perfect partner for architects and contractors across the UK.