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Community and Q&A

Locating ERV Air Intake

NICK KEENAN | Posted in Green Building Techniques on

I’m installing an ERV. The ME wants to put the air intake on the rim between the first and second floor. I want to put it below the first floor for aesthetic reasons. He says it’s better to have it off the ground because the incoming air will be less humid. Is air more humid closer to the ground? I’ve never heard such a thing. Is he right?

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  1. Trevor_Lambert | | #1

    In theory, it's the opposite. Humid air is less dense than dry air. In practice, there may be other variables, but I'd say his statement is essentially false. I think I heard that air near the ground is "dirtier"; whether that's allegedly dust from the ground or fumes from the car in your driveway, I'm not sure. I would think that as long as it's above the maximum expected snow level, it's fine.

  2. BirchwoodBill | | #2

    I would check the building science website. I thought they recommended something like a minimum of 12 inches off the ground. My design is for radiant cooling, so it goes through an air filter, water coil, HRV then dehumidification.

    Conceptually the ME is right from a science perspective, but I don’t know if it works from a practical perspective.

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