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Ducting ERV to exterior

user-6310848 | Posted in Mechanicals on

My situation is that an ERV is located in the center of a 1960’s A-frame deep retrofit. I need to duct fresh air from the gable end of the structure and i am planning to go under the house (ion piers) . So the question is: Do I need to insulate the fresh air duct to prevent condensation?

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  1. user-2310254 | | #1

    What do the manufacturer's instructions have to say?

  2. GBA Editor
    Martin Holladay | | #2

    The usual advice is that once the fresh air duct penetrates your thermal envelope, entering conditioned space, you need to use insulted duct.

    Will the duct pull the fresh air from the space between the floor assembly and the dirt under the house? That's not ideal.

    Your post raises many questions, including this one: Are you sure you are locating your ERV in the most logical spot in your house?

  3. user-6310848 | | #3

    Martin and Steve, thanks for you thoughts. The location of the ERV is not ideal however there are no good solutions in this situation. The mechanicals are all in a 3X6 closet. The constraints and dilemmas of an A-frame on piers are many. The fresh air will not be pulled from the crawl space. It will be ducted from the gable end and then penetrate the floor at the ERV.

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