GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter X 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

ERV ducting question

eagleeyeshawk | Posted in General Questions on

Hi All,

I live in Nashville. We are building a 5800 sqft two story custom home, with 5 bedrooms and an office.

Our builder is planning on using the ducted Mitsubishi hyper heat mini split for hvac. We are going with an ERV and currently he is planning to use the hvac ducts.

We are having an engineer do the manual J and D and whatever else, but will the engineer make a rec for ducting the ERV separately?

I think I would prefer dedicated ERV ducts but cost limitations may force us to use the hvac ducts. How bad is this? How much would dedicated ducts costs?

Any help and considerations are appreciated.

Thanks for reading!

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. the74impala | | #1

    It is impossible to tune an ERV per room with the HVAC ducting. It will just draw or flow to wherever.

    I plan to use a Zehnder unit at my current project. More expensive, but very tunable and efficient. They send pretty much everything in one package, plus sending someone to calibrate it during the commissioning of the system.

    Not exactly something that would be easy to retrofit later, so it will never be cheaper than the present.

    Hope they consider a dehumidifier with all that humidity in Middle Tennessee.

    Something else to consider, are you going to house your hvac in an unconditional attic? Hope not. See Matt Risinger's videos about that on YouTube.

  2. eagleeyeshawk | | #2


    Thank you for responding. Indeed the ERV will likely be in the attic. We have some cathedral ceilings so there will be 3-4 inches CC SPF on the roof deck and open cell below that. Should be okay, per Martin’s recs.

    It’s interesting, builder initially was planning on doing a whole house ventilating dehumidifier. I soured on that after reading a GBA article that noted a stiff energy for having a ventilating dehumidifier.

    I will look to get a quote from zender and see what the numbers looks like. They have an online method I can supply info and they will get back to me with a quote.

  3. user-2310254 | | #3

    You may or may not need mechanical dehumidification. It’s important to monitor conditions after you move in to stay ahead of potential problems.

Log in or create an account to post an answer.


Recent Questions and Replies

  • |
  • |
  • |
  • |