Calvin Henry-Cotnam wrote:
Joseph Meehan ) said...

Calvin Henry-Cotnam wrote:

HOWEVER, the frame needed to support three panes of glass is a
better thermal bridge than what is needed for double. On many
windows, the gains in R-value for triple is offset, or WORSENED by
the frame.


Interesting. I suppose that would be possible. Do you have any
source of figures for it?

Unfortunately, I don't. This was explained to me by a window
manufacturer, who had a monetary incentive to sell me triple over
double, so I consider "facts" coming from him that suggest I go the
other way to have a little more weight to them than most "facts"
thrown at me.

Looking at other posts, I see mention about aluminium frames and this
jogs my memory a little more on this issue. The extra support that is
needed for triple tends to come from aluminium components. Even with
a thermal break, I tend to believe that the benefits of triple glazed
windows over double are not realized until the area reaches a certain
threshold.

What exactly that threshold is would be interesting and useful to
know.

Thanks for responding. Your logic makes sense, but of course the devil
is in the details.

--
Joseph Meehan

Dia duit