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Community and Q&A

ERV/HRV with zoned heating/cooling

user-6905873 | Posted in Energy Efficiency and Durability on

In a house with zoned heating and cooling (multi split VRV type ductless system with many zones), does a centralized ERV/HRV defeat the purpose of the zones?  

I know there are decentralized Lunos and Zehnder type ERV/HRV systems, but having a bit of street noise, I’d prefer to minimize the number of holes I’m cutting in the walls.  If I were to go with a single/central ERV/HRV, how much will it mix the air of my zones?  If I have one room/area/floor with no AC and another room/area/floor with AC, will the centralized ERV/HRV completely mix all the air and override the zones?  Or is the amount of mixing minimal and I will still get the efficiency benefit of not cooling areas I don’t use very often ?

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  1. GBA Editor
    Martin Holladay | | #1

    First of all, can you tell us your name? (I'm Martin.)

    An ERV or HRV does not perform a significant amount of mixing in a home. It does not operate like the air handler of a forced-air heating and cooling system.

    Ventilation air flows are low. A properly commissioned ERV or HRV system might deliver only 10 cfm of fresh air to a bedroom (whereas a forced-air heating system might deliver 100 cfm or 200 cfm when operating).

    When the ERV or HRV is operating, 100% of the fresh air it is delivering to your living room or bedroom is outdoor air. It isn't mixing air -- it isn't pulling air from one room and delivering it to another.

    During the winter, the air delivered by your ventilation system will be colder than conditioned air inside your house. During the summer, the air delivered by your ventilation system will be hotter than conditioned air inside your house.

    If you have a zoned heating and cooling system, the thermostats in each zone should be able to maintain the temperature settings you choose, with or without a ventilation system.

    1. hobbysqueek | | #2

      Martin, Thanks for the reply. I was searching for this for so long and you explained it beautifully. For NorthEast (PA) would you recommend hrv or erv? Also how does it work in the summer?

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