Furnace Venting Through Roof

When the vent is withdrawing air from the house it expels the gas outside through the vent.

Furnace venting through roof.

The penetration will be oval to have a round pipe exit vertically through a pitched roof you need an oval hole in the roof. Also known as the type b this vent is operating on the natural air convection. This vent is designed to be used on 4 in. Another problem is that flue pipes that go through the roof tend to be less efficient.

It is easier to go through the wall next to the furnace and makes it a lot easier to deal with. Direct vent systems have versatility to their installation that natural vents do not. If your furnace has an afue rating of 90 percent or above it will have a flue pipe that goes out of the side of your house. Piping can be set horizontally to allow venting through a sidewall or vertical installation can also be undertaken to allow venting through the roof.

The master flow 4 in. Goose neck vent the master flow 4 in. Run the vent pipe up through the roof and install a metal or pvc flashing collar over it. If your furnace has an afue rating below 90 percent it will most likely have a flue pipe that goes up through your roof.

Position the vent pipe up to the bottom of the roof. Twist the roof s vent pipe clockwise one half turn with one hand while holding the gas furnace s vent pipe still with the other hand. Go into your attic. If your furnace has an afue rating of 90 or lower it probably exhausts the gases though the flue pipe on your roof.

High efficiency furnaces take advantage of the heat in the combustion gases that are wasted in natural ventilation systems. Push the male end of a new vent pipe up through the bottom of the roof flashing and set its female end on the male end of the vent pipe that connects to the gas furnace. Match the vent pipe to the furnace maker s recommendations either sheet metal or vinyl. The collar s job is to create a tight seal keeping rainwater and debris from getting into your attic.

These collars consist of a metal base generally made out of aluminum and a rubber boot integrated into the top of the collar. That depends on whether you have a standard efficiency or a high efficiency furnace. That s because the combustion byproducts are in a gaseous form so the gases can float up through the flue pipe and out of your roof. If you are venting a high efficient furnace with the pvc piping you can go through a roof or wall.

Also no chimney is needed regardless of whether horizontal or vertical installation is used. Installation of direct venting is fairly easy but more costly than the b vent type. With the pipe in a vertical position trace around the pipe using a pencil.