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Daily attic air exchanges?

79YTT | Posted in GBA Pro Help on

.. with a balanced attic ventilation system in place,

how many attic air exchanges daily should be expected?

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Replies

  1. GBA Editor
    Martin Holladay | | #1

    Hans,
    I'm not sure what you mean by a "balanced attic ventilation system." If you are referring to air inlets at the soffit combined with air outlets at the ridge, the air flow through these openings varies widely. On a windless day in winter, when snow covers the ridge vents, you will get very little air flow (especially if the ceiling is air-sealed and the attic floor is well insulated). On a windy day, you will have very high air exchange rates.

    However, you are perhaps referring to an attic with a powered attic ventilator (a fan). If that's what you are talking about, I urge you to disable the powered attic ventilator.

    For more information, see:

    All About Attic Venting

    Fans in the Attic: Do They Help or Do They Hurt?

  2. BobHr | | #2

    What is it you are trying to accomplish with attic venting. Do you think that more air flow with keep it cooler and keep the home cooler. Do you think there is to much humidity and you are worried about mold?

    In the summer radiant heat is the main means of heat transfer and the air flow will do little for keeping the house cool. In fact it will likely suck air out of the house.

    The best thing you can do is air seal the attic floor and insulate.

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