assaigs de productes i la seva normativa

Rating windows according to energetic performance

Pregunta: I would like to know which systems (if any) are currently in Spain for rating windows in terms of their energetic performance.

Respuesta:

We do not have references about any initiatives in Spain about systems for "rating" windows from the point of view of energetic performance. Anyway, we do agree that such an initiative would be a sensible idea, because:

• The market is already used to have windows tested against the "rating" system provided by EN 42, EN 77 and EN 86. We are sure that in your country you are also are familiar with this system, that classifies the products into different categories according to their resistance against air (the "A" factor), water ("E") and wind ("V").
• The only reference for energetic performance that technicians are using is the thermal transmission factor of the glass. This approach treats the window much the same as any other construction element -for instance, like a brick wall- when the window acts in a quite different, less "passive", way.
• The average technician does not know exactly how to deal with that alternative approach to the window as a "non-passives" element in the energetic performance of the building. Glass manufacturers are offering new products labelled "solar-control glass" or "low-emission glass" which are supposedly more advantageous than standard products. The problem is to know how much they improve the energetic performance, and how to choose between them.

Of course, such a system would not have to be limited strictly to windows, but also other derivatives like curtain walls.

Fecha de la consulta: 12/04/2003

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