i think i can better help you if provide some details of your setup
i'm going off the assumption that your growing in your own house.
where in the house is the grow space located?
how big is it?
is your basement finished? what i mean by finished is, sheetrock/painted, ceiling instead of just floor joyces
is there no window because the space you chose has no exterior walls?
if i go off the assumption that your space is 4X4 ft, on the first floor of the house, all the surrounding walls are interior walls, and you have a unfinished basement. also assuming you have a HID light w/ hood, and inline fan.
then i would say, in the corner of the growspace cut 2 holes right next to each other, in the floor the size of the duct you will be using on your reflective hood(4",6" or 8"). run your exaust duct from your light through one hole in the floor, and out a window in the basement. you can zip-tie the ductwork to the floor joyces along the way, so its not hanging all over the place.
then buy a duct flange (hxxp://www.htgsupply.com/Category-Flanges.asp).
buy an air filter that is larger then your hole in the floor (hxxp://www.lowes.com/Heating-Cooling/Air-Filters/_/N-1z0znaz/pl?Ns=p_product_qty_sales_dollar|1).
cover the hole with the filter, and screw the flange onto the floor, over the hole & filter. the filter is not for purifying the air that enters the room. its just to keep insects out, mostly. if done properly. when you turn on your inline fan. it will suck the hot air out of the room, through your duct, and safely out of your house. this will cause negative pressure to build up in the grow room. cool c02 enriched air will be suck from the basement through the hole with the filter over it. i believe they call this passive air exchange.
hope this helps, green mojo for your grow.
SB