N Gas Dryer Install Info

['Stormin]

Tried to get an answer at Lowe's. I have never had one of these. Can't figure out if the 4" air discharge will be in same place or not no matter what brand? OR do I have to buy one first before trying to rough in Gas Valve and 4" Vent?
They guy said 4" vent would be in center of machine. I am scepticle.
I like the idea of the "Dryer Box" that insets into the wall framing. Anyone actually installed one of those?
I will be doing a downflow into crawlspace and then about 20' of rigid metal duct to get outside of house wall.
Supposedly the absolute largest size dryer is about 7.3 Cubic Feet. A larger size doesn't change anything about installation does it?
Thanks.

[plumberscrack]

I like the idea of the "Dryer Box" that insets into the wall framing. Anyone actually installed one of those?

Sometimes when I'm roughing in plumbing for laundry the customer will ask me to hook up the dryer as well. The dryer box is all I use now.

http://www.dryerbox.com/intvid.htm

['Stormin]

Thanks, Sure looks like a better way to do it. Only other way I've found is to precisely cut hole and mount the vent pc. from outside the house once the dryers in place but that only works if strait out the back and still drafty.

[Hondahead]

I will be doing a downflow into crawlspace and then about 20' of rigid metal duct to get outside of house wall.
If your crawl space is a "cold zone" the duct must be insulated, all joints must be taped, NO SCREWS. I like the inset dryer boxes, they are the norm up here.