We have a CYV and experienced mold in the master bath. Eventually we purchased a dehumidifier, keep it in the master bath with the door closed and now no more mold...problem solved. It's amaing that we collect two gallons of moisture in 24 hours on humid days even though we have the AC on. We have a humidistat and even with the AC humidity in the house goes up and down along with the outside humidity.

Having a window in the bathroom in Florida with the outside humidity being so high would probably not help. I. I have installed timer switches on all my fans so when I go in to take a shower I push a timer button and it stop Stays on my pre selected time then shuts off never had mold.

I have two windows in the bathroom and never open them as there is more humidity outside. Never in 10 years had a mold issue.

I recommend putting in a Panasonic Whisper Choice exhaust fan and a separate timer at rhe switch plate (don’t get the more expensive one with the built-in sensor. These are much quieter than most fans, and they exhaust 110 cubic feet per minute, compared to probably 40 for what you probably have now. Use the timer, set for an hour. Probably that will leave your shower walls dry, and your towels, too. Panasonic is the top-rated by both the Journal of Light Construction and Consumers Reports. Having an open window in your bathroom lets in a lot of humid air that then has to be cooled and dehumidified by your air conditioner. This exhaust fan is cheaper by far than the extra AC.

They are sold at Lowe’s and Home Depot, but unless you are very good at this sort of thing, hire someone to put it in for you.

Solar Tube
 

Have a solar tube installed. Call Solar Guys, (352) 205-4204

our CYV garage 24x24 has a window facing the street

We never open our bathroom window. The problem most likely is your temp setting for the AC. Keep temp at 73 to 74 and the humidistat at 54%. I am assuming you may have a Carrier heat pump.

And your neighbors will get to enjoy your singing in the shower, Neighborhood concert.

That might be possible because I have two windows on that side one is a frosted glass window in the shower and the other is a very small window above my bed. So it might be possible to add a window but, not one you can open to let in fresh air!

Get a better fan
 

You don’t need a window, IMO.

The standard fans they install are absolutely garbage. We always had mold and mildew problems in our bathroom (not a CYV) but last year installed a better fan with a built in moisture sensor. It cuts the fan on for about half an hour whenever the shower runs and removes the moisture before it can do damage. Made all the difference in the world. No more problems.

Do you happen to know the make and model #?

Bathroom window
 

You could leave the exhaust fan on for several years to equal the cost of the window, especially if your house in concrete block.

window
 

get a sky light that open Electric :wave:

A tubular skylight would be less if window can’t go.

I have 10 ceiling fans in my home (block and stucco designer) including 2 in garage and one in master bath. I could not live w/o them. Run both ceiling and exhaust fan during and after shower and my mirrors don't even fog up.
Works great. Only open windows to air out house in winter as hot, humid air is not fresh air to me.