Converting atmospheric vent to direct or power vent?

by Marko

I am planning to upgrade my gas water heater atmospheric or natural draft flue with a DV or PV type. I have a small house with a basement where I am planning to install my new gas water heater, preferable high efficient model.

The outside basement wall and possible vent termination has a nearby window and the patio doors.

Please help, how should I choose the right vent location and other pros and cons.


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Mar 22, 2014
Go Direct
by: JR

There are three types of water heaters you can choose from: power vent, direct vent and power direct vent. Every type has its own pros and cons.

The power vent water heaters utilize the electric fan to remove the products of combustion out, and these models draw the air from the inside the house. Keep in mind that these heaters cannot be connected to the chimney and share venting with other appliances due to the negative pressure that can affect the performance. It is recommended type if you have to run a long pipe and want flexibility in installation.

Direct venting is recommended for homes if you do not want to be electricity dependent as these units remove the flue gases using the difference in pressure between the hot flue air and outside colder air. And you don’t have to worry about possible spill as these units use the outside air for combustion and have the sealed combustion chamber and pipes. Also, these models make no noise since there are no movable parts, they require much less maintenance so less things to go wrong and worry you.

With the DV heaters, chances of the house going under a negative pressure are minimal. The pipe inside the pipe type allows you to have the vent termination at one point. The negative is the limitation on distances.

Power Direct vent is used when the indoor air quality is a concern. It draws the fresh air from outside for combustion while removing the exhaust gases with the use of the fan.

Regarding your concern about the closeness to the windows and other opening… there are codes that oversee where a vent for certain water heater can be located, meaning how far from the door, window, deck, exhaust for the furnace and so on.

Your plumber should follow the local building codes and gas codes that are related to this problem. You can also consult the manual for your particular unit.

Keep in mind that improper venting might lead to carbon monoxide poisoning (it is odorless).

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