Direct Vent Zero Clearance Fireplaces can be installed just about anywhere. They do not require a chimney, and can be vented through the wall or roof. They are a cost effective way to lower your heating cost. These units often use thermostats or remotes to control the temperature, with automatic fan systems. The fans are usually an option that is well worth getting. All gas fireplaces radiate heat, but fans circulate the heat back into the room.