Warm edge – Update

April 15th, 2017. Not that long ago, during GLASSTEC 2016, several new spacer solutions for thermally improved glass edge bond were introduced. My latest article for the GLASWELT-magazine gives an updated overview of the systems and informs about the latest trends. You can find the article (in German language) here.

Lukewarm edge? Does not exist!

February 5th, 2016. Just to clarify again: “warm edge” refers to insulating glass edge bond with a thermally improved spacer. There is a clear definition of “thermally improved”. It can be found in the relevant international standard for the thermal transmission coefficient of windows, ISO 10077 part 1, as well as in the standard ISO 12631 for the thermal performance of curtain walling. Both standards contain each a chart with linear thermal transmission coefficients Ψ (Psi-values) for spacers made of aluminium and steel and a second chard with lower values for spacers with thermally improved performance. In cases of coubt, the definition helps to decide which chart is the right to use.

According to this definition, spacers made from steel are definitely NOT thermally improved. “Warm edge” does begin with stainless steel spacers. Stainless steel has a considerably lower thermal conductivity compared to aluminium or steel – it’s not for nothing, that the handles of steel cooking pots are often made from stainless steel.

Therefore, it is definitely not ok to praise steel spacers as somehow thermally improved. And by the way: Just the colour black alone does not provide sufficient evidence for a good thermal quality. Lukewarm edge – something like that just does not exist.


Warm edge – Profile bars of the future

May 28th, 2015. There are different approaches to thermally improved glass edge bond: hollow profile bars (“rods”) made from materials with low thermal conductivity, flexible foam spacers on coils or thermoplastic material from drums. You can find an overview of the presently offered “rods” in my latest article in issue 5/2015 of GLASWELT here, including a glimpse at the future of warm edge (Article is in German language).

Impressions from BAU 2013 Munich

January 18th, 2013. How nice to almost exclusively see triple glazings with warm edge spacers in the exhibits of the wooden and pvc window producers of Hall B4, C4 and B5. It has got around that warm edge is advantageous because it improves the Uw-values. The further distribution of warm edge is unstoppable, same as for triple glazing.

Metallic systems though seem not yet to have taken the message entirely. Hall A1 still contained quite a few exhibits with double glazings, often with aluminium spacers. What a pity, considering the high thermotechnical sensitivity of metallic window and facade systems to the improvement of the transition area between glass and frame. The use of warm edge makes technical sense and is a economic measure. As for the next BAU 2015, I am confident that regarding spacer and glass, also the exhibits in hall A1 will be up-to-date.