Different Ways to Vent a Fireplace

Why Vent

• Venting a fireplace accomplishes two things: bringing air into the firebox and taking exhaust away from it. Smoke, carbon monoxide and other byproducts of burning fuel escape your home through the vent, as the exhaust is warm and travels upward. The upward draft that's created pulls air to the fire from inside the heated room, aiding combustion. Without proper ventilation, the smoke would come into the room from the fireplace, bringing with it poisonous carbon monoxide gas. Even with the correct vent installed with your fireplace, you need a carbon monoxide alarm that will sound when it detects high levels of the odorless and colorless gas in the room.

Chimney

• Chimneys are one of the oldest forms of venting fireplaces, and they are still useful today. Chimney venting allows smoke to escape from a wood fire. Today, those with wood-burning fireplaces or built-in gas fireplaces can still use chimneys. An annual cleaning of the chimney by a professional sweep and a check of the lining will keep use of a chimney safe. During use of the fireplace, the chimney damper needs to remain open for proper venting. Close the damper when the fire is not in use to prevent heat loss from your home and to prevent rain or animals from getting down the chimney and into the fireplace.

Direct Vent

• Direct vent fireplaces use gas as their fuel. A vent pipe runs through the wall behind the fireplace and outside. Unlike vertical chimneys, gas fireplace vents run horizontally. These use the vent to provide oxygen for the fire and an outlet for smoke. To keep the smoke from billowing into the room and the fire from using room oxygen, the front of these fireplaces is completely covered with thick, heat-proof glass. Heat from the fire is pushed into the room with convection fans under the fireplace.

Ventless

• Ventless gas fireplaces are controversial when it comes to building codes. Some municipalities' building codes do not allow for their installation at all, but others restrict the installation of ventless gas fireplace units to large rooms and bar their use in in bathrooms and bedrooms, according to Carson Dunlap in "Principles of Home Inspection: Steam, Electric Wall/Floor Heating." These units operate by burning more completely, to eliminate carbon monoxide as much as possible, and they do not require exterior venting. Room oxygen fuels the fire in these units, which is why they cannot be installed in small spaces. One of the byproducts of using ventless fireplaces is the large amount of condensation they produce if the unit is not the right size for the room. Because they do not need a vent pipe, ventless fireplaces can be installed anywhere your local code allows without cutting into walls or putting the unit next to a chimney.