new cage

I have a 2 year old BP and it is growing out of its curent cage. I would like to buy a new cage but the one that i am looking at is a glass tank with a screen cover. 36"X18"X16" is that to big my snake is about 4 feet. Is there anything I can do do keep the humidity up while still have that screen. Or should i look at other cages.
Thanx

thats a great cage for her. just cover part of the screen with anything you can think of that could keep the humidity in