The Differences Between Direct & Vented Fireplaces

Chimney

• One of the most obvious differences between a direct vent fireplace and a vented fireplace is the existence of a chimney. Vented fireplaces, also called B-vent and natural vent fireplaces, use chimneys as the main source of smoke and air suction. This type of system uses air in the room to feed the fire. The fire draws the room air to itself, heats it and sends it up through the chimney to the top of the house where it is vented. A direct vent fireplace, "direct" referring to the specific air channel that feeds the fire, uses an inner pipe to vent the exhaust and channels air from an outside pipe to use as fuel for the fire. The air from this fire vents either through an outside wall or through the roof. Such a setup can use an easily installed pipe instead of a chimney.

Enclosure

• Another difference between direct vent fireplaces and vented fireplaces is the need for an enclosure. The enclosure is a barrier that separates the fire from the room but allows air to flow through. Such a barrier usually takes the form of a metal grate, a chain metal curtain or glass panels. Although an enclosure is often used in natural vent fireplaces, it is not a requirement because the air feeding the fire is coming from the front of the fire. Conversely, direct fireplaces are fed from outside air received from a pipe at the rear of the fireplace. While still very safe, this does create the possibility for flareup due to strong winds. Because of this, direct vent fireplaces must have an enclosure on the interior side of the fireplace to prevent uncontrolled spread of the fire and possible disaster.

Efficiency

• Although both types of fireplaces burn fire in the home, direct vent fireplaces are more efficient than natural vent fireplaces. This is because the design of a direct vent fireplace allows heat to radiate uninterrupted from the front of the fireplace into the room. Natural vent fireplaces use this same area to both radiate heat and feed the fire, which can cause a drop in the amount of heat radiating into the room while simultaneously providing the fire with less oxygen than a direct vent fireplace.

Depth

• The depth at which a fireplace must be recessed into a wall often dictates where the fireplace can be installed. Natural vent fireplaces require more depth than their direct vent counterparts because of the need for proper upward ventilation. Because direct vent fireplaces vent through a series of pipes, they need not be recessed so deep into the wall and can be installed in a wider variety of areas in the home.