Nonvented Vs. Direct Vent Gas Logs

Gas Fuel Source

• Both direct vent and nonvented gas log fireplaces rely on natural gas as a fuel source. This means you do not need to stock wood in the fireplace, even if the fireplace appears to have wood logs inside. The logs in a direct vent or nonvented fireplace are synthetic and do not burn. You do not need to keep wood on hand and as long as the natural gas supply to your home is not interrupted, you can run the fireplace. One option with a direct vent gas fireplace is to install it in an old wood-burning fireplace. After making some quick adjustments, you can still burn wood if needed or desired.

Placement

• Nonvented gas fireplaces provide more flexibility in their placement since you do not need to hook the fireplace to a vent pipe that can reach the exterior of the house. If you live in a condominium complex, a nonvented fireplace may be the only kind you can use if you cannot obtain permission to run an exhaust pipe through the top of the building. With direct vented gas fireplaces, you can position the fireplace only where you can run the exhaust pipe through the house and out the roof.

Safety

• Safety may be a concern if you are considering a nonvented gas fireplace over a direct vented fireplace. Direct vented fireplaces allow the carbon monoxide produced by the burning of the natural gas to escape the house safely as long as the fireplace’s exhaust pipe is not damaged. Nonvented gas fireplaces may burn up too much of the oxygen in your living space, putting anyone in the house at risk for carbon monoxide poisoning, which can be fatal. The fireplaces should have an oxygen-detection sensor designed to shut the fireplace off automatically if the oxygen levels in the house approach dangerously low levels.

Humidity

• A nonvented gas fireplace may raise the humidity in your house versus a direct vented fireplace. When you burn natural gas, the reaction produces water vapor. This water vapor sits in your house’s air, condensing on cold windows, exterior doors, the house’s attic and even your house’s exterior walls if they are not insulated well enough. The water vapor trapped in your house may lead to water damage or mold growth. When you run a direct vented gas fireplace, you can see the water vapor coming out of the vent pipe or chimney in the house’s roof, releasing harmlessly into the outside air.