i'd go through the chimney if possible. depending on where you live it might look suspicious with a bunch of steam coming out of a sewer vent on your roof for 12+ hours a day in the winter. Steam comes out of everyone's chimneys in the winter. just make sure your exhaust doesnt backdraft through any of your natural gas appliances like your water heater or furnace unless you want carbon monoxide poisoning and to kill your family and pets. also i saw this thing where a grow got busted in alaska and the dude vented out the wall horizontally and the condensation froze into this gigantic block of ice. wicked obvious. always vent to atmosphere vertically if possible