Thermal performance: fenestration: the reality explained

#thermal performance #windows

When the time comes to choose their #windows either for a renovation or a new construction, the informed consumer will be interested in the thermal performance of the coveted product.

However, it is unfortunate to note that several players in the industry are posting performances that are far from reality.

The purpose of this post is not to put anyone on trial, but simply to set the record straight and provide fair, relevant and enlightening information.

Thermos

The thermo has its own performance. Let's take an example of a lab test result posted by a competitor on their website, on a 1.23 meter by 1.48 meter window:

#performance #explanations #windows #thermo

In this example, the value obtained for the thermo only is 0.7 W(m2K). By using a better quality thermo, a better performance will be obtained, but always considering the dimensions of the thermo.

So the Ug provides us with the information of the thermo performance only.

In the equation:

- quality of glazing;

-glazing number;

-choice of spacers;

-gas type;

-thermo dimension;

Thermo performance is still only part of the story. You are not buying just a thermo, but a complete unit with frames, opening or fixed and hardware.

The profiles (frames)

The equation should then contain the thermal value called Uf.

The same lab report as in the example above contains this table:

#exampleperformanceextrusions #windows

We see that: top, bottom, sides and mullions each have their own performance.

Overall performance

The consumer should be interested in the overall performance of the product for each position.

In the above example the result of the lab test reveals the following:

example of thermal performance explained

#thermalperformancewindows

For illustration, we have always used the same certificate displayed by a competitor. Although the content of the certificate is unambiguous, the merchant displays a performance of its products up to U 0.53 (R11), while this information is contradicted by its own documentation, this value being valid only for the thermo-only.

Difficult for an informed and vigilant consumer to navigate!

The right intellectual approach:

The resulting true thermal performance of the product you are purchasing should consider:

-The size of the window;

-Is it a sash or a fixed one. Fixed window will have better performance;

-Choice of hardware for the openings and their ability to close hermetically;

-The quality of the thermo and its intrinsic performance;

-The quality of the extrusions including the number of chambers;

The real performance of the product is in the calculation made once assembled and for each position, according to their respective dimensions.

Next time a merchant gives you a thermal value:

Request the value for each of the project positions for the entire product once assembled.

At VST