There are two main types of direct vent fireplace. In direct-vent appliances you use special direct-vent pipe recommended by the supplier. Fireplace Insert Venting Demystified Fireplace Inserts Vented Gas Fireplace Direct Vent Gas Fireplace A direct-vent unit is 70-85 efficient. What is direct vent fireplace . This type of fireplace has a completely sealed combustion chamber which allows it to vent directly out a side wall of the home. Direct vent fireplaces have several advantages over traditional gas fireplaces in terms of safety efficiency and versatility. Fresh air is pulled from outside of your home into the fireplace and the exhaust is expelled through a separate pipe back outside. Direct-vent units can also be installed in masonry fireplaces or framed inside your home. They feature a firebox sealed with tempered or ceramic glass and use a dual-purpose vent that both vents exhaust to and pulls combustion air from the outdoors. They burn cleanly are energy efficient a...