I squeegee the shower walls and floor after I shower. There's very little left to dry, so I can turn the fan off when I leave the bathroom.

The OP doesn't have a lighting issue. Why in the world would you install a solar tube to prevent mold?

Thanks for all the replies.
I take showers early in the morning when heat and humidity is low. It's not hot and humid year round and still would be nice to be able to keep the window open for fresh air during cooler months without having to put the main unit fan on.
As far as privacy I can go in my back yard and see my neighbors if I wanted. I'm not a peeping tom and planned on having the window high up on the wall.
Anyway I'll contact ARC.

Look into a skylight that opens. I was in a couple of homes in TV that had those.

You cannot go into the yard on the windowless side of your house without the prior permission of your neighbor. That area is a side yard easement that is controlled and maintained by your neighbor. According to the Deed Compliance office, ARC has routinely disapproved applications to install a window on that side of the house because it affects the neighbor's privacy in their fenced-in back yard. Note that even if you did install a window, your neighbor could erect a landscaping screen or other type of barrier to block the window, as long as it was not attached to your exterior wall. Your neighbor can do almost any type of landscaping in their back yard, but they cannot attach anything directly to your wall.

Same

I think you missed my point, I can stand in MY yard and see over the fence at my neighbors.