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Articles > Direct Vent Gas Products

9 Oct 2006


Direct Vent Gas Products
Direct Vent gas appliances offer higher efficiency than Bvent (Natural Vent) gas appliances. Natural vent appliances use room air for combustion (to provide air to fuel the fire). Direct vent appliances use one of 2 styles of dual piping systems; onepipe brings air from outdoors to provide combustion air, and the other pipe vents exhaust fumes. We prefer the term "balanced flue" for direct vent appliances, as this term succinctly describes how this system operates. A direct vent system balances combustion air with exhaust air.

Why are Direct Vent Systems More Efficient?

Direct vent gas appliances are tested under ANSI standards for fuel efficiency. Unlike a decorative appliance which is not tested for efficiency, you can be assured that you're getting better heating results for your energy dollars. They do not use heated room air to provide combustion air.

They are not affected by "air tight" homes. Since they are designed to provide their own combustion air from outside the building, their operation is not dependent upon the available air inside your house. Installed properly, they function predictably and reliably in any home. If your wood burning fireplace is experiencing drafting problems that cannot otherwise be solved, a gas insert with a co-linear direct vent system will provide you with a means of having a fire that works predictably and reliably every time you use it.

Natural draft generally must rise. Natural draft appliances, therefore, must have a vertical vent system. Direct Vent appliances (including fireplaces and freestanding stoves) can be installed with co-axial pipe in a horizontal configuration. This allows installation design flexibility as a fireplace can be installed against an exterior wall and reduce the amount of exhaust pipe needed for your fireplace design. Direct vent pipe can also be used in vertical configurations to clear the roof with most appliances, but check manufacturer specifications for your model. Horizontal pipe configurations may save considerably on pipe costs AND give you the flexibility to install a fireplace or stove nearly any where.

Direct Vent appliances do not require electricity to operate, other than any blowers that may be available on your model as an optional or included component. Most models now use a millivolt valve system that even allows remote control or wall thermostat operation, even if the power is off, so they provide a comforting backup heat source if your home loses electricity.

For more information on planning direct vent installations, click here. Remember, your installation must conform to the appliance manufacturer's tested and approved design configurations which will specify horizontal and vertical length limitations.
Co-Axial Pipe
A pipe within a pipe; combustion air enters through the outer chamber and exhausts exit through the inner chamber. See components.
Co-Linear Pipe
2 separate pipes, used inside an existing chimney. One pipe brings in combustion (supply) air while the other pipe carries away exhaust & fumes. Usually made of  2-ply aluminum, co-linear pipe is lightweight and flexible, and easy to install. Details.

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