How to tell if a window has a thermal break

The window is one of the key elements when we look for a good thermal insulation of the house. Both in the frame and in the glass heat losses occur, so it is important to know how to choose a good window.

In particular, thermal break must be taken into account. It is advisable to know what it consists of and the importance it has to isolate our home from outside temperatures.

What is thermal break

Thermal break (RPT) is the separation that is placed when a material is a good conductor of temperature. In the case of windows, separation is done using a material that is a poor thermal conductor.

What windows can RPT have

When we compare windows we are going to find 3 possible materials: aluminum, PVC and wood, but it is the windows with aluminum frame that must have RPT.

This is because both wood and PVC are poor thermal conductors. In both cases it is not necessary to make a thermal break.

Therefore, when comparing aluminum windows, you will have to opt for those that have RPT versus those that do not.

How to identify if a window has RPT

Depending on the window you want to look at, it will be more or less easy to identify it.

When you go to buy it

At the time of purchase it is very simple. You will only have to look at the description to know if it has thermal tip breakage. Here is an example of the Leroy Merlin that does incorporate it:

Window with RPT
Window example with RPT

Here instead we have another example of a window that has no RPT.

Window without RPT
Example of window without RPT

As you can see it must incorporate the acronym “RPT”. You can ask the manager (he will know how to tell you at the moment which of his models have RPT) or look directly at the description. As it is an essential characteristic, it must be well indicated.

When it is already installed

In the event that the window you want to analyze is already installed, you will have to pay a little more attention. To make it clear, here’s an image of the profile of an aluminum frame with RPT.

Aluminium window with RPT
As you can see inside the sheet and frame there is a layer of a different material. It is polyamide, a plastic that acts as a thermal breakdown between the two metal parts.

This material can be detected by hitting with a metal piece. You should notice how the sound is slightly different, since its hardness is less.

Another characteristic of polyamide is color. While aluminum is silver, the color of this plastic is black. You will not be able to see it with the naked eye, since you will find a layer of paint all over the surface, but if you scratch it you can see the color of the material.

If it is silver it will be aluminum, but if you see a black material in the central area you will know that it is polyamide. And therefore you will know that it has RPT.

In addition to checking the RPT, I also recommend that you look at the tightness of your windows. On windy days bring your hand to the edges of the closed window or bring a lit candle. So you can check if some air enters.

If this is the case you should put some weather strips throughout the profile. Allowing air to pass through the window gaps will mean an increase in heating consumption, since heat will be constantly lost at this point.

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By Catharine Bwana