Related Terms: Downflow furnace, Register, B-vent, Exhaust fan, Venting, Direct vent, Air vent, Damper, Bellows, Ventilate, Upflow, Make-up air, Exhaust, Ventilator, Hood, Blower, Air duct, Downflow, Vent-free, Plenum, Pneumatic, Backdrafting, Draft hood, Draft, Combustion air, Air diffuser, Secondary air, Grille, Flue, Air pump, Ductwork, Air shaft, Air hose, Makeup air, Laboratory fume hood, Compressor, Primary air, Supply air, Air lift, Natural ventilation, Central air conditioning, Bleeder, Air handling unit, Vent, Aftercooler, Condensing unit, Plenum chamber, Ambient air, Ventilation , Breather