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Recommended ERV that can be unbalanced to slightly over pressurize house?

Gwisejr | Posted in Green Products and Materials on

Boy would I love to install a Zendher Qxxx ERV in our home that is being built. But I can’t really pony up the $12k install for such a unit. I like the Panasonic Intelli-Balance but I would like a unit that can ramp up from a lower CFM to a higher CFM via a timer so that I can use it in place of a regular bathroom fan. 

Can I get any recommendations of manufacturers to look at? This is going to be a self install as I will have access to all rooms from the ceiling.


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  1. Expert Member


    Just to clarify - Are you asking for an ERV that does two things: One that can be used as a substitute for bathroom exhausts by using a boost function, but also one that can be unbalanced to provide positive pressurization?

  2. Gwisejr | | #2


    Correct, I've seen that some units have accessory control items like programmable push button timers that will boost the CFM's for 10, 20, 30 min. So in normal operation it is exchanging at what ever you've calculated the needed Air exchange rate is. Then push the button in any of the bathrooms or kitchen and the motors kick up to a higher rate for the specified time. Preferably with the positive pressure imbalance still in effect.

  3. Jon_R | | #3

    When the bathroom is at 100% humidity (from showering), the last thing I want is positive pressure pushing moisture into the walls. So I'm curious why you want positive pressure?

    1. Gwisejr | | #4

      So, reason for positive pressure is that we are building on an agricultural lot and we've just found out that son had allergies to hay and other stuff. As to the concern that you have, I would think that since the ERV returns are in those higher humidity areas, the pressure difference to outside would be negligible. Plus we're not talking about a high pressure difference for the rest of the house. Just enough so that on balance, most of the replacement air is coming thru the ERV and filtered as oppose to any leaks in the air barrier.

      1. Jon_R | | #5

        Makes sense, at least during some weather. Note that it can take large amounts of airflow to create small shifts in pressure - this depends on how well the house is sealed. Also note that stack effect and wind pressure can easily overwhelm/reverse purposely induced pressure.

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