I have a large sliding window that is 53 inches top to bottom and I want to install a portable air conditioning unit. The kind that don't sit in the windows but vent to the window. The window exhausting expander thing that come with these units seem to never be large enough.
Can I just use some plexi-glass or something to extend the extender or is there a better way?
Update:
I found one large sliding window vent kit, but I think its just for edgestar ac units and I'd rather not have to buy such a kit if I can get a good seal some other way.
Best Answer
You could build a wood frame that fits in the window with an interior hole large enough to accommodate the AC unit. This also has the advantage that you won't have to hold the window open, while juggling the unit into place. You can install the light weight frame, then slide the unit into place.
I built one when I lived on the second floor of an apartment building, because I was always afraid I would drop the unit out the window while installing it. I used foam tape around the exterior and interior of the frame, to make sure I got a good seal around the window and AC unit.
For a unit that only vents through the window (not sits in it), you could build a smaller frame with a port to allow the vent to pass through. Filling the interior of the frame with Lexan will reduce the amount of wasted window space.
(You could always use smaller lumber for your frame, if you want it to have a lower profile. The frame size in the image is just an example, to illustrate the idea).