Bathroom window bisects drop ceiling

[Wesley W.]

Hi all,

I'm doing a renovation on a building I purchased and I'm looking for ideas on how to navigate this issue.

As pictured, in the bathroom there is a drop ceiling, and the height of the window (which is within the tub surround) is higher than the drop ceiling.  

This leaves a gap where most air from the shower can rise up into the void above the drop ceiling.  There is a ceiling fan installed, but I am not sure that won't disuade most of the air from moving right past the drop ceiling via the gap, which will almost certanly create moisture issues over the long term.  One thing I can do is rewire the fan to turn on with the nathroom light switch, but I am not sure that would be enough.

I'm looking for a solution that is the least intrusive/involved but still remedies the problem.

I would rather not:

-replace the window with one of a smaller size (this would involve disturbing the asbestos siding on the exterior, which is on the second floor, and doing a fair bit of demo to the inside wall)

-raise the height of the drop ceiling (which would leave a 4 or 5 inch gap between the upper part of the wall panels and the drop ceiling grid; I plan on keeping the wall panels but replacing the tub surround panels)

So...who's got a creative fix for this?

Thanks in advance!