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My question concerns the best way to ventilate a remodeled post-and-beam open plan house.

j_g | Posted in General Questions on

We reduced our post-and-beam house to its beams and are building it back up again, but with no walls except for those in the two bathrooms. The house is 900 square feet with an attached solarium of 200 square feet. There is a loft area that covers about 60 percent of the ground floor. We have a cathedral ceiling with 6 inches of closed foam insulation between the shiplap ceiling (showing the exposed beams) and the roof sheathing (similar to that shown in FHB O/N 2007). The walls will have 3 1/2 inches of closed foam insulation.

The plumbing is stacked with the upstairs bathroom over the downstairs bathroom (which itself is next to a laundry cupboard).

As I indicated, the house plan is completely open. I read with great interest the comments on ventilation options, but my situation is slightly different from that of other questioners.

The house is located in Southern Maine about 15 miles inland from the coast.

Should I just use only bathroom exhausts or an HRV system exhausted through the bathrooms, both bathroom exhausts and and a separate HRV, or some other option?

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  1. j_g | | #1

    I forgot to mention that we will be using hydronic radiant heat in the downstairs floors.

  2. GBA Editor
    Martin Holladay | | #2

    It sounds like you are undecided between an exhaust-only ventilation system and a balanced system using an HRV.

    As I wrote in my blog about ventilation options (, exhaust-only systems can work well in a small house with an open plan, like yours. An HRV system will cost more to install, but will provide heat recovery and will provide a system that does a better job of distributing fresh air evenly.

    If you are worried about where to locate the ventilation ducts, they can be boxed in or exposed. Many commercial jobs use exposed ductwork -- for example, spiral metal duct.

  3. homedesign | | #3

    It will no doubt cost much more for ducting and equipment if you decide to go HRV.
    At least your home sounds simple...and potentially tight.
    Perhaps the cost of ducting(labor & material) would not be so great?
    What if you "pre-Ducted" and prewired for an HRV?
    The incoming air duct and exhaust ducts would need to cross near each other.

    Or... at the very least provide yourself a path so that you or a future owner could add Energy Recovery in the future...
    equipment will improve and prices should come down.

  4. j_g | | #4

    Thank you both for your answers. Would you advise me to exhaust the bathrooms separately from the HRV system? The way the house is laid out I might be able to make both systems simpler than if I combined them -- but I could use the bathrooms as the intake for the HRV.

  5. GBA Editor
    Martin Holladay | | #5

    The exhaust air for an HRV system is always drawn from the bathrooms (and sometimes the laundry room) of a home. The question was recently discussed at length here:

  6. homedesign | | #6

    Another reason that "combining" makes sense to me is that it reduces the number of "openings"...
    Combining and reducing plumbing vent stacks is good too.

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