Prewar Bathroom exhaust fans

1) Why not just put standard bathroom exhaust fan into the already existing bathroom exhaust duct?
2) Similar to what you do with an AC or dryer exhaust: put a piece of plywood in the window and cut out a hole for the fan.
3) Something most people don't do and I don't know why: instead of using a simple on/off switch, use a timer switch.

Good ideas, but

1) prewar with window--there is no exhaust duct
2) As in most prewar with window--the window is in the bath/shower, so plywood and dryer duct probably wouldn't work.

I was thinking of just having an intake fan in the door (then crack the window open to make the humid air exhaust that way) but alas, can't even find a good fan to mount that way.

Sounds Art Deco; most other prewar that I've seen don't have the window in the tub area. A layout would help.

Go to www.grainger.com. No lack of fans there.

JustAnother, you're pretty much stuck.

There're little round fans that go into a cutout in the glass, but they're more for ventilation rather than exhaust, and power would be a problem over a tub.

You might want to try a dehumidifier. It might not be able to quickly cope with shower steam, but would help in keeping mildew at bay. Probably a useful thing to have in NYC, anyway.

I've got both kinds of bath: exterior windowed and interior exhausted. The interior one will still steam up occasionally, and the window in the other is almost always open.

I got a shorter window then the current bathroom window and had metal box for the exhaust put in above it with the grill and trim finished with the exact same color&material as the original window. On the inside the bathroom ceiling was lowered 4 inches for the duct work and built in a slim Panasonic exhaust fan. Works very-very well. The bathroom window was not in the front/facade of the building.