# using acrylic plexiglass to make an old window "double pane"



## av-geek (Jan 15, 2012)

I have a nice bow window on the front of my home, but the problem is that it is single pane glass, and it's like having a huge hole in the front of the house. I am thinking of a good idea of taking some acrylic plexiglas, and cutting it to fit over the mullions, then fastening it down with small screws to make like a double pane, with an air gap of about 1 inch between the original glass, and the acrylic. I can do this with about $250 worth of acrylic.

Does this sound like it will work good? Am I wasting my money with minimal results or is this a great, inexpensive way around buying a new bow windows for $10,000 or so. I know it's not going to be as tight as a new window, but I am hoping it will make the living room at least a little less drafty. I am thinking that moisture settling in between the layers may be a problem, and for that reason I don't want to seal the layers together, but be able to remove the screws, take the acrylic panes off, and clean any condensation off. Also, the screws would insure there would not be a "perfect" airtight seal and the layers could breathe a slight bit and avoid the moisture problem altogether.

What are you thoughts on this? Crazy or kinda smart?

Here's a picture of the window I cropped from a Christmas photo. The mullions are about 3/4 inch wide. I also plan to cut acrylic for the openable portions the same size as the screens.


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## HomeSealed (Jan 3, 2008)

Same concept as an interior storm. In fact, you may want to explore that option for a superior fit and finish. Regarding the seal, it is precisely that which will keep moisture from building up between. No seal will result in more condensation on the outer unit, similar to what you see on most storm windows. 
Another thing to keep in mind is that the seat and head of that unit may not be well insulated either. Adding 2" of XPS foam board to the exterior of that seat board would help.


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## Fix'n it (Mar 12, 2012)

HomeSealed said:


> Regarding the seal, it is precisely that which will keep moisture from building up between. No seal will result in more condensation on the outer unit, similar to what you see on most storm windows.


exactly. seal them up. i have 2 old wood windows, right next to each other.
they are going to be replaced. but to make them better, to get through this winter. i took the sashes from same size windows that i did replace. put some caulk on them and screwed them on = 2 pane window. i works great. the other has a little gap (that i didn't catch until it got too cold to fix). and it fogs sometimes.


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## BigJim (Sep 2, 2008)

Plexi-glass will yellow and become cloudy in no time and will scratch easily, it would be a waste of good money to use that. I will leave the advice up to the window experts here about the windows, just wanted you to know about the plexi-glass.


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## joecaption (Nov 30, 2011)

Add it crazes to the list.
Something's really wrong with that price for a new window.
Get some more prices.
Stay out of the box stores!


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