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Balanced ventilation

user-6896983 | Posted in Energy Efficiency and Durability on

I have read several articles on this subject.  I am trying to build as airtight as possible.  I also plan on incorporating an ERV with my HVAC unit.  I also plan on installing some sort of fresh air vent for my cook-top and vent hood.  My question lies in the exhaust vents for the bathrooms and laundry.  I am having trouble finding what others are doing to help balance the air when a bathroom vent is running or your clothes dryer is running.

Thanks,
Travis

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Replies

  1. Trevor Lambert | | #1

    You shouldn't have bathroom fans or a clothes dryer vent, if air tightness is a goal. While there's a good argument to be made that an externally venting range hood is a worthwhile concession, I don't think there's really a good argument for putting holes in your new house for either bathroom fans or a clothes dryer.

    Note also that it's preferable for the ERV or HRV have its own ductwork.

    https://buildingscience.com/documents/information-sheets/info-611-balanced-ventilation-systems

  2. GBA Editor
    Martin Holladay | | #2

    Travis,
    Most homeowners find that operating a clothes dryer doesn't cause any problems. The air flow requirements of a clothes dryer (usually 100 cfm to 200 cfm) aren't high enough to cause backdrafting problems.

    If you are like Trevor, and you don't wand a dryer vent, you can get a condensing clothes dryer or a heat-pump clothes dryer. But most homeowners just specify an ordinary dryer.

    When it comes to bathroom exhaust fans, you need to decide whether you even want one. For more information, see "Does a Home with an HRV Also Need Bath Fans?"

  3. user-6896983 | | #3

    Thanks guys. A little more detail. This will be a 2 story with basement. A little over 4000 sqft. There is a full bath in the basement, a half bath on the main floor, and a full guest bath and master on the 2nd level. The master will have an enclosed water closet, stand alone tub, and separate shower. I have specified a variable speed Daikin unit in order to turn over the air for the entire house several times a day. Originally the HVAC co. was planning on using a multi-point ERV w partial connection to the air handler with stand alone exhaust fans for the bathrooms. After reading these articles again, it might make more sense to completely separate the ERV from the air handler. I could vent the half bath and all the fixtures on the second level with the ERV while the variable speed air handler will still circulate air through the rest of the house. That would only leave the full bath in the basement that would need vented. I believe it might be too costly/difficult to try and include the basement into the ERV. Will discuss with the HVAC co. Am I missing anything in this scenario? Are there any issues with moisture buildup/mold using an HRV/ERV with long trunk-lines to exhaust moisture? Also, in the winter it is helpful but in summer you are just redistributing the moisture. I am pretty sure the HVAC unit has a dehumidifier on it but will it be able to keep up? This is in E TN.
    Thoughts?

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