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Community and Q&A

HRV for a 3000 SF All Brick Multi Wythe home in MN?

tenNmw58np | Posted in Mechanicals on

We have an almost 300 sf Brick load bearing wall home in MN. There will be no insulation in the home but in the attic (We won our case with the city because of the risk on insulating the walls). There will be drywall installed on the furring strips on the walls. We are installing a kitchen hood that is a 600cfm. Wondering what size HRV is required, and what rooms are recommended to have the vents in.

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  1. jklingel | | #1

    If I recall correctly, the code calls for 1 cfm/100 sf of living area, plus 7.5 cfm/person. That leaves you with 45 cfm. Exhaust the stinky rooms, fill the clean ones, but apparently don't get too close to the kitchen hood. See an HRV person for "too close". Why no insulation in MN? That is not necessarily a warm State.

  2. GBA Editor
    Martin Holladay | | #2

    Kristina isn't installing any wall insulation because she has an older house with load-bearing multi-wythe brick walls. Such walls can be tricky to insulate on the interior because of possible moisture problems.

  3. GBA Editor
    Martin Holladay | | #3

    Minnesota requires homes to include a mechanical ventilation system:

    It's been a while since I have written any articles about the Minnesota ventilation code, and I'm not sure of current code requirements. In any case, you should consult a local home performance contractor or HVAC contractor to be sure that your planned ventilation system meets the Minnesota code.

    If the code references ASHRAE 62.2, then an HRV is one option but is not required. An exhaust-only ventilation system may satisfy the Minnesota code.

    Remember, an older home is usually leaky, so you may already have quite a bit of air exchange in your home.

    For more information on ventilation systems, see Designing a Good Ventilation System.

  4. tenNmw58np | | #4

    Thanks. I will check with our HVAC people here. I made a typo in the questions, our home is 3000 sf, not 300. But I will check our resources here about the HRV.

  5. wjrobinson | | #5

    Kristina, contact a professional, best IMO.

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