Direct vent is a term used to describe a specifically designed fireplace that performs differently from the traditionally vented fireplace which use a chimney. This type of fireplace has a completely sealed combustion chamber which allows it to vent directly out a side wall of the home. One of the benefits of this type of design is that it must draw air necessary for combustion from the outside since the sealed combustion chamber does not allow air to be drawn in from around the fireplace. The co-axial vent system has the exhaust pipe within the air intake pipe which protects any surrounding combustible material from the high temperature of the flue gases as well as preheating the outside air prior to it being introduced to the combustion process.