Advantages of a Direct Vent Fireplace
On a winter night, the last thing you want to contend with is a cold home. To combat the chill, you might bundle up in flannel pajamas, make yourself a cup of hot chocolate, or if you're lucky, snuggle beside a cozy gas fireplace. However, if your gas fireplace isn't a direct vent fireplace, you're losing heat up the chimney.
A traditional gas fireplace uses indoor air for combustion. It takes air from inside the home to burn natural gas or propane and sends the fumes up a flue. A flue is a vertical pipe that exhausts the gases naturally by drawing them upward and out of the home through the roof. The hot gases rise through the flue to the outdoors, because warm air naturally rises above cooler air.
Traditional gas fireplaces are considerably inefficient because they allow conditioned air to escape the home through ports in the firebox and through the open doors of the fireplace. Another problem with their design is that backdrafting can occur if, for instance, a kitchen fan is pulling air out of the home. The depressurized indoor air can pull harmful gases back into the home instead of exhausting them outdoors.
Direct vent fireplaces have several advantages over traditional gas fireplaces in terms of safety, efficiency and versatility. A direct vent fireplace uses outdoor air instead of indoor air for combustion. It pulls in air from the outdoors through the outer chamber of a double vent pipe; the inner chamber of this pipe exhausts fumes. The natural flow of heat creates a convention loop; as hot air exits the pipe, cooler, denser air is siphoned in to fill the void. Since direct vent fireplaces generate cooler combustion gases, no flue is needed; the pipes can be installed through the wall.
Safety. Direct vent fireplaces eliminate the need for a flue through the roof, so backdrafting isn't an issue. As another safety measure, the vent pipe can be installed through the wall with a fire-caulked flange.
Efficiency. Direct vent fireplaces burn natural gas or propane like traditional fireplaces; however, they convert most of the fuel to usable heat. They are completely sealed off from the interior rooms by a glass door, which prevents significant heat loss.
Versatility. Because direct vent fireplaces can be installed through the wall, they can be placed anywhere in a home. If you don't have wall space, these fireplaces can also be vented upward through the roof. Though direct vent fireplaces tend to be shallower than traditional gas fireplaces, they are available in many widths and heights.