recess niche on exterior wall

Hey all, was looking for some advise on a tub surround. 2X4 construction and owner wants recessed niche in wall (exterior) - tub and valve are set. Sounds like a bad idea to me = no insulation and back of niche only 1 inch from minnesota winter.
Any thoughts?

Ice will form. Then they will have they're very own tiny little ice cave.

I'll ask if that is what she wanted - I aim to please!. Just looking for other ideas I may not have considered. Vent stack on back side and valve on front. Corner shelves will probably be solution.

Corner shelves are good!

That's the beauty of pex. You could wrap a piece of pex from the valve to the drop ear for the shower arm and place the niche in the middle of the wet wall. Pex will have no frictional pressure loss. I like having my own plumber to shoot ideas back and forth.

But corner shelves are outstanding too.

Sorry, just woke up. You could wrap the pex around framing for a niche in the wet wall is where I was trying to go with my first response. Back to my coffee.

I knew what you meant!

So you have your own plumber? Where do you keep him?