Do equal sight lines windows have equal sized glass ?


15 Jun 2006
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United Kingdom
I am in the process of ordering new PVC double glazed units and am going for equal sight lines throughout (using dummies for non opening windows). My question is will this result in equal glass sizes on each window?

My supplier says it wont - there will be small differences - say in a four pane window the outer panes will be slightly narrower than the inner ones (150-200mm narrower). Something about how they measure a window.

Is this right?

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Yes and No I will try and explain as best i can :confused:

Depending on the design of the window, the mullion centres will be unequal but the glass will be equal(outer frame to mullion,mullion to mullion etc) frame and mullion are different thicknesses hence the reason why the glass sizes are unequal if you centre the mullions.

However if you centre the glass the mullions are unequal and the glass is equal.

I always centre the glass (design permitting) when lead designs or georgian bar is involved it looks a lot better. :)
Thanks Kevash. I now understand.

My windows are Georgian - like you do most suppliers centre the glass ? My supplier tells me differences are hardly visible and the vast majoriy of homes even with equal sight line windows have the mullions equal and not the glass.

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