This is my studio window and the fan that I use for exhaust. Inside measurements of the frame are 14 3/4" w x 64 3/4" h. the outside measurements are 40" w x 68 3/4" h. This is a very good fan that works well. The challenge is that I don't want it so near my head as I paint because of noise. It's not all that noisy, but you know the hum it's there all the time, most of the time I run it on medium speed for adequate ventilation and on high speed when heavy fumes are apparent and clears the entire room and space around, no worries. I don't have much of a budget to work with but not impossible with patience. I have skill to do this myself and tools and resourceful for materials. I haven't resolved a design that would work and be safe in construction and reliable to work with. Any ideas? This morning I spent 2 hours, 3rd try to replace the duct tape around this window that works real well when it is -40C/-30C outdoors. The 1st attempt was removing old weathered stuff, 2nd attempt was a fail with inferior tape, got it on the 3rd attempt with superior quality, perfectly well sealed from any freezing cold air leaks. Any new design changes here will be implemented in springtime, most likely.