Aluminium Windows: A Complete Guide

Windows can have a significant impact not only on the look of a property, but also on the security and efficiency.

Choosing the right window for your project can be a daunting task and there are many factors that need to be considered such as style and performance.

Here at Sieger we produce aluminium framed windows, among other aluminium glazing products, at our state of the art manufacturing facility.

Aluminium is long lasting, eco-friendly, and flexible in design, making it an excellent material for glazing frames.

 industrial style aluminium casement window with glazing bars

Types of windows

Flexibility in design is a key element when it comes to bespoke and beautiful glazing.

At Sieger we have a range of windows to choose from in a variety of configurations, sizes and colours.

Side Hung

Most residential properties have side hung windows, and at Sieger any of our window systems can come in this configuration.

If a minimal and modern design is required, we have systems with ultra slim framing. Alternatively optional glazing bars can be included in the design  for a more traditional aesthetic.

Top or bottom hung

It is not uncommon to see top hung and bottom hung windows in residential properties

Top hung windows are excellent for the UK as they can be opened whilst it’s raining and not let the water inside.

Bottom bung windows can be a popular choice for buildings such as hospitals and universities, where there may be people at risk of falling from a window.

Tilt and turn

Tilt and turn windows have a versatile design and flexible ventilation options. These windows can be tiled open to allow for ventilation without losing heat from the house but can also open as a normal side hung window.

We have two windows which have the option to be manufactured in a tilt and turn configuration, the Sieger 70 Window and the HD option for the Sieger Slim Casement.


Fixed windows can be stand alone or surrounding doors to fill the structural opening. Our fixed gable end windows can be designed to fit almost any roofline shape to create a statement window design.

 external view of aluminium tilt and turn windows
gable end window paired with a casement window in a bedroom

How much do they cost?

There’s a variety of factors which affect the cost of a window such as size, configuration, frame finish and glass specification.

Our Sieger Aluminium windows can start at approximately £550 p/m2, however this is only a rough estimate and can vary greatly depending on the above mentioned factors.

To get a quote for your windows get in touch with the team.


How long do they last?

Aluminium is one of the most long lasting, durable materials used for glazing framing.

Not only is aluminium corrosion and rust resistant but at Sieger we can Polyester Powder Coat our aluminium frames with any RAL colour for extra protection .

The average lifespan of aluminium framed glazing can be up to 45 years, which is an extensive life compared to uPVC windows which have an average life expectancy of around 30 years.

One main advantage of aluminium windows is that they are largely maintenance free, however there are steps that can be taken to ensure they last as long as possible.


How can you prolong the life of aluminium windows?

Making sure the right protective coating is applied to the frame is the first step in prolonging the life of your aluminium glazing.

Polyester powder Coating (PPC) is the standard finish for aluminium frames and at Sieger we can use a PPC finish in any RAL colour desired.

If the glazing is going to be in a harsh environment, such as a marine environment, there are other finishes such as a marine grade coating that can be applied.

Cleaning twice a year with the right products and carrying out yearly checks are other steps that can be taken in ensuring your glazing reaches its full potential. Read more about these here.

Why choose aluminium windows for new builds?

New build homes must meet certain standards, and in recent years there has been a big focus on making your home more sustainable.

Aluminium is 100 percent recyclable and all Sieger window frames are thermally broken to achieve modern thermal performance values.

All Sieger window systems come with double glazing as standard but can be specified with triple glazing to achieve the highest levels of insulation.

New build homes often follow contemporary architecture trends which can include sleek modern designs.

Many of our systems have ultra slim frames so can blend in seamlessly with minimal building designs.


Why choose aluminium windows for period properties?

Renovating period properties can come with many challenges, like figuring out what is allowed by the planning permission board at the local council.

When selecting replacement windows for a period property, one of the most important things is that the glazing does not change the original property features.

Many of these properties originally would have had steel or timber window frames and aluminum can be used to replace either.

Period properties often had single glazing with slim sightlines, which can be replicated with the Sieger Slim Casements minimal frame.

The fact that Sieger windows can be designed in a range of styles means that they can mimic the style of the original windows, so the over aesthetic of the property is not altered.

top hung casement window with glazing bars for an industrial steel look
aluminium top hung windows with fixed gable end windows

Thermal performance

Thermal performance can be a significant decider when it comes to selecting a window.

Factors to be considered are whether the unit is single, double or triple glazed, whether the frame if thermally broken and what the U values of the system are.

All Sieger windows are double glazed as standard with thermally broken frame and a low e coating on the glass.

It is important to remember that some companies give the Ug value which only refers to the glass, instead of the Uw value which is the overall performance of the unit.

This is because most heat is lost where the glass meets the frame. Sieger always provides all thermal values like for the Sieger Tilt and Turn Window which has Uw values from 1.0 W/m2K. 


Security performance

Security is another factor to consider when choosing windows.

There are a few factors that can affect the security of windows such as whether the glass is toughed or if the glazing is internally or externally beaded.

Sieger windows all come with toughed glass as standard and all systems are PAS 24 certified.

All Sieger Window Systems are internally beaded so no one can remove the beading from the outside to make an entry point.

When choosing a window these are critical deciders as security is something that should not be spared.

If a window system does not have an adequate security rating or uses float glass, they may be putting the property and people inside at risk.

Window restrictors

Safety regulations require upper floor windows must be fitted with some type of window restrictor.

If windows are being fitted in a place where there are young children or people who are vulnerable to the risk of falling window restrictors may be required, even on the ground floor.

These safety devices come in many forms such as a holding restrictor or a child safety restrictor.

These restrictors are not always necessary but should be considered when choosing your window systems.

Depending on the fire escape plan for the building it also may be necessary to have fire escape windows.

Fire escape windows have to be able to open enough for adult to get out of in the event other routes are blocked.

In the UK, this is usually defined as being able to open without obstruction to at least 0.33m2.

oversized slimline aluminium windows
large aluminium floor to cieling casement window

How to specify Sieger windows

There are many specifications used to evaluate window performance such as wind load and thermal performance.

Expert specification is often needed as windows must be in compliance with any building regulations, which can be complex.

We are able to provide up to date information for all products, most of which is available on our website but the Sieger team can answer any additional questions.

Sieger can provide architects with an NBS specification sheet created by us to assist them. These can be found on the website or request one from the sales team.

Once you have spoken to the Sieger team and received a quotation, and order can be placed.

All Sieger Window Systems can be manufactured as part of a whole glazing package.


For more information or to discuss you project in more detail contact our technical team by calling 01494 722 882 or emailing [email protected]

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