Since Chinese elm is one of the few species that can be grown inside or outside, you need to determine which one you will observe. If you are going to keep it inside all the time, then yes, it will need some humidity, but you don't have to take it in the shower, you can just spray it occasionally to keep the dryness from your house from affecting it. You may want to email me at:
wchoat@american-bonsai.com so I can send you the lengthy care instructions for Chinese elm. You may also want to check my site:
http://www.american-bonsai.com