The Side Downdraft is a very popular booth for those who want a full-downdraft, but do not want the expense of excavating an exhaust pit (or simply can’t), nor want a raised exhaust basement. Air enters through the filtered booth ceiling and down to the floor, exhausting out the bottom of the side walls. Exhaust plenums behind the filters is collected to a vertical plenums that leads to the exhaust fans (one fan per side).
An air make-up unit can be added by ducting to a plenum above the ceiling filter section.