GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter Instagram YouTube Icon Navigation Search Icon Main Search Icon Video Play Icon Plus Icon Minus Icon Picture icon Hamburger Icon Close Icon Sorted

Community and Q&A

Ventilation: continuous and spot combined?

user-1137156 | Posted in Energy Efficiency and Durability on

Facts:   Airtight homes need continuous  ventilation to maintain indoor air quality.  Bathrooms and kitchens need spot ventilation.  This looks like a viable way of addressing both continuous and spot requirements in a single, properly ducted system.  Is there a better way?


GBA Prime

Join the leading community of building science experts

Become a GBA Prime member and get instant access to the latest developments in green building, research, and reports from the field.


  1. canada_deck | | #1

    It's a step in the right direction.

  2. Deleted | | #2


  3. STEPHEN SHEEHY | | #3

    Our HRV boost switch is in the master bathroom. We hit the switch when we turn the shower on, setting the timer for 30 minutes. Works fine.

  4. this_page_left_blank | | #4

    Seems like a good idea, but the obvious question is how much difference is this going to make?

    From what I can tell, the only difference between this and an ERV with a boost switch, is the switchable dampers in the exhaust registers. This would allow, in theory, boosting to a specific area. What's not clear is how balanced ventilation is maintained in this way, since the supply registers don't have the switchable dampers. I guess the undamped exhaust could just be stealing air flow from the other exhaust registers, but this doesn't look like what's happening in their demonstration video. In the animation, they show an increased flow from ALL the return registers, and no flow increase from the supplies. Where is the make-up air coming from in this scenario, or is this just an inaccurate representation of what the airflow would look like?

    Does this work significantly better than just boosting the ERV? I would guess not.

    And how much more does it cost for these special registers, and the associated wiring? Not insignificant, is my guess.

    Lastly, how efficient is the ERV at the core of this system? Not very; 62% at 106CFM.

    1. user-1137156 | | #5

      The difference,as I understand it, is: With the Aldes ZRT system the flow rate increases ONLY at the selected location, all other exhaust grills maintain the regulated flow rate, in other words all the added flow comes from the selected location. In other systems that have a " boost" mode all exhausts see the same proportional flow increase. It should be noted that the Aldes ERV is balanced by controlling the fan speeds and doesn't use balancing dampers. Most other brands use balancing dampers.

Log in or create an account to post an answer.


Recent Questions and Replies

  • |
  • |
  • |
  • |