Direct venting only works with specially designed gas appliances, according to The Chimney Sweep, Inc., and is not for use with wood burning stoves. Wood burning stoves require a vertical chimney that extends through the roof.
Heating appliances that burn fuel, whether wood, gas or heating oil, to produce heat also consume oxygen. If there is not a vent to replenish the oxygen the fire depletes from the room, levels sometimes drop to the level that it is uncomfortable or unhealthy for human and animal occupants. With direct vent technology, a double-walled pipe that exits horizontally from the back of the gas stove exhausts the combustion fumes and provides oxygen for the fire. The sealed firebox releases heat without affecting oxygen levels in the area.
If there is not an existing flue in the home, manufactured chimneys are one option for homeowners who want to install a wood stove. These flues have two or three concentric pipes. Some have insulation, and others have sealed air construction. They exhaust smoke and fumes from the fireplace but do not provide a fresh air supply.
Efforts to provide make-up air for the wood burner have problems, according to the Green Building Advisor. Most are proximity vents and do not connect directly to the stove. They tend to dump cold air into the room that is heated.