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Opening or sliding aluminium frames?

In this article we will help you to clarify the characteristics of the two types of frames.

As we are used to hearing, every door that we open in our lives is important and that is probably a great truth. What is not specified in the above saying, however, is whether that door is… sliding or opening! Choosing one or the other is certainly of great importance. Depending on one’s space, there is one that suits and serves one’s needs. In this article we will help you to clarify the features of the two systems in your mind . Thus, you will be able to make a proper comparison of the different elements that aluminum frames have. What matters above all else is to choose the most suitable one for you.

Aluminium window frames

Opening frames are very popular and are preferred by a large number of customers. One of their main advantages is their insulating capacity, both in terms of thermal insulation, waterproofing and soundproofing. In all these areas, aluminium frames have an excellent performance (of course we always refer to aluminium frames with thermal insulation and not to non-insulating or ‘cold’ frames), while their performance in terms of safety is equally high. In addition, opening aluminium frames offer a wide range of designs and can be accompanied by a screen, shutter or external shading roller blind.


The disadvantage of opening frames is that they cannot support very large openings. We are of course referring to openings of 2 metres or more. A hinged system cannot serve us as effectively in this situation, even with a double-leaf French door. Also, in terms of space saving, it is not an ideal choice for homes with very limited square footage, such as very small apartments. This is because they always require extra space inside to allow the balcony door or window to open unobstructed.

Sliding aluminium frames

Sliding frames are very often found both in city apartments and in detached houses. In the first case, sliding windows contribute to the space saving required in an apartment. Similarly, in the second case of detached houses, there are sometimes large openings that could not be supported by a sliding frame.


Also, the current trend in architecture worldwide is to have as little visible aluminium as possible. The rationale is to highlight the minimal aesthetic in this way and allow light to pass unobstructed into the interior. In this case too, sliding frames are preferred, as they can be configured to match the minimal aesthetic. This includes: thin leaves, recessed-hidden frames in the masonry – so-called ‘sliding recessed frames’, ‘superimposed sliding frames’, etc.

It is worth noting that usually a sliding system cannot reach the level of thermal insulation of an opening system, as in the opening system the tightness is enhanced by the insulating rubbers around the leaf and the frame. However, we must not forget that we have to compare similar cases. In other words, there is a possibility that a highly advanced sliding system may catch up with the performance of an opening system. Such is the case with lift-and-slide systems, which ‘snap’ into the driver, providing high thermal insulation, and are lifted by a special mechanism so that they can be easily towed.

The glass factor

Whatever your final choice is, you should not forget that the thermal insulation performance of aluminium windows (and all types of frames in general) is directly related to the type of glass they “wear”. The glass usually occupies 70%-80% of the total surface area of a window frame. Thus, it makes perfect sense that it has a very strong influence on its behaviour. There is an overabundance of options in this area. Therefore, it is important to discuss the type of glass and its characteristics with the professional who will install your windows.


One element that we should always check is Ug (g from Glass), which is the thermal transmittance of the glass. Together with the Uf (f from Frame), which measures the thermal transmittance of the frame and leaf, they make up the Uw (w from Window), which is the overall thermal transmittance of our window or balcony door. The smaller the above indices, the lower the heat loss we have, so small indices equate to better performance for the aluminium systems we choose. A quality aluminium system can provide thermal insulation and security, but without an equivalent quality glazing, the overall performance will not be at the maximum desirable level.

Summing up


The choice of new frames is crucial, as it affects living in many ways. We need to be informed and aware. Whether our decision is based on aesthetic criteria or on criteria related to energy efficiency. Buying windows and doors is an investment that comes to complement our lifestyle in everyday life. So why shouldn’t this investment improve our lives by making them pleasant and functional? Feel free to decide on your new aluminium windows but most importantly decide with knowledge!

Source: alumil.com