Sup 99!!!! well if you build the box in yr attic and you have means to exhaust into yr chimney happy days!!!!
When im exhausting into the waste pipe it hides 90% of the smell but that 10% is still very strong this is always an issue for me,, without going and buying or making a carbon filter this is the best solution i could find,, in fact if yr handy with yr hands theres a great thread on here sumwhere showing how to make yr own carbon filters for less than a price of a c.d!!! its a very clever method that i will be using on my next grow!!! one thing you should never under estimate is the smell,, if yr just beginning i would defo look into making one just to eliminate any nosey fuckers sniffing around

i will be watching yr thread...good luck bro.