Venting a Tankless

    Tankless Venting

    There is a plethora of information regarding tankless systems and which is right for you. This can be an intimidating experience for any consumer, today we are going to deal with venting and choosing the right method for your application. There really is no right or wrong choice it’s that some situations will require different methods and we aim to help you choose the option that best suits your needs.

    Use the information below to the best of your ability, but if you have a unique situation send us a quick email or give us a call and we would be more than happy to help out.

    Tankless systems require oxygen or air to complete and maintain the combustion process. It is essential for tankless water heaters to precisely monitor and control both the incoming and exhaust gases to achieve peak efficiency. As time goes by natural and environmental occurrences build up reducing a tankless heaters ability to efficiently heat water. Different venting systems have different traits let’s look at some of the different characteristics.

    Non Direct Vent Indoor (fan assisted)

    1. Uses a powered fan to push exhaust gases out of the house
    2. Pulls the air or oxygen needed from the inside of the house
    3. Fan powered tankless systems allow for increased flexibility in venting (vertical or horizontal)

    Direct Vent Indoor (fan assisted)

    1. Combustion oxygen is taken from outside the home, eliminating thermal drafting issues inside.
    2. The Tankless water heater is sealed and doesn’t consume any air form the inside of the house.
    3. Venting is done with two pipes or a single concentric pipe (a pipe inside another pipe).
    4. Can be used in locations where appliances may be competing for the same oxygen or in cold climates where air leakage reduces home energy efficiency.
    5. Vertical or horizontal venting


    1. This is restricted to warm weather climates only as subzero temperatures significantly reduce efficiency and there is a risk of the unit freezing
    2. Air for combustion is taken directly from the environment around the unit.
    3. Improves home energy efficiency as excess heat is thrown off outside and reduced A/C load.

    Author: John

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    1. You can mount them on pretty much any interior and exterior wall. Your situation shouldn’t be a problem for a tankless at all.

    2. Does a tankless hot water heater have to be mounted on an exterior wall? We have a conventional hot water tank at the moment and will be replacing it. It vents threw the roof, three levels higher up. Can the exhaust of a tankless be run horizontally 20 feet indoors before it exits threw an exterior wall? Or will it have to be mounted on the exterior wall directly?

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