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HRV Reliability

Nathan_6
Nathan_6 Member Posts: 40
I agree we balance the system to .35 ACH but then we also control the unit so it only operates x amount of minutes per hour instead of running continually as there is know need to exchange the air when know one is home.

Comments

  • nathan_8
    nathan_8 Member Posts: 8
    HRV units

    What Hrv units have you had the best reliability with The local supply houses carry the Venmar/Broan line and the FanTech models. It has been years since I've installed any HRV units and they were mostly Vanee and a couple Broan units and both brands had their problems.

    We have a few projects coming up were the customer has asked for us to install a dedicated standalone HRV unit for there home and was wondering what everyone's opinion was on the Venmar and fantech models?
    -The fantech look to be cheaper to operate because of their EBM motor's found on all units.
    -The Vanee units seem to have a better sensible apparent effectiveness at both the warm and cool temps.

    Both of the homes are small units requiring around 80cfm total flow.

    Any thoughts??

    Thanks.
  • MikeyB
    MikeyB Member Posts: 696


    The Eneready HRV's are the holy grail where I live. Made in Burnaby BC, Eneready specializes in only HRV's. I've serviced a few that have been neglected that were doing fine. They offer them with the Posh system if you want to use them as your bathroom fan as well.
  • Paul Pollets
    Paul Pollets Member Posts: 3,656
    HRV's

    We use the LifeBreath appliances and have for 15 years. Never a problem. We order the machines with the ECM motor upgrade. 80CFM is a small load, we generally design for 35cfm per room, which is code in the state of WA.

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  • Nathan_6
    Nathan_6 Member Posts: 40
    35 cfm per room???

    Wow that code seems pretty poorly written what if a room is a small 10x12 bedroom with 8 foot ceilings at 35 cfm that works out to 2.18 air changes an hour. Or stated another way the total volume of air in that room is changed out 52.32 times in a 24 hour period. Or say it was a very large open basement or large living room with high ceilings then the 35cfm might not be enough. Codes that use a fixed CFM per room instead of a calculated air change rate could potentially add a tremendous heating load and inefficiency to the home or have the opposite effect and not effectively ventilate the home.

    Here we design for .5 ACH which for the same size room works out to 8cfm needed to accomplish that. when it is 10 to -20 degrees outside the last thing you want to do is be reheating that small bedroom 52 times a day.

    Glad to hear good report on the Life breath units as we are looking to install one of their fan coil units in a home that is undergoing a scorched air to boiler retro fit.


  • ASHRAE calls both of those numbers ridiculously high. 0.5 ACH on high speed, I can see for temporary high exhaust situations, but don't operate units at 0.5 ACH. You don't need anywhere near that for normal occupant health.
  • Paul Pollets
    Paul Pollets Member Posts: 3,656
    Correction

    the code reads ".35 air changes per hr". We still design for 25-35cfm per outlet.

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  • Nathan_6
    Nathan_6 Member Posts: 40
    why??

    Why would yopu still design for 25-35 cfm per outlet when you only need .35ACH? You are designing each outlet for a 1000sqft room.
  • Paul Pollets
    Paul Pollets Member Posts: 3,656
    Design

    We use the LifeBreath design guidelines manual, and are able to achieve more than the minimum air exchange. Since the HRV's have multiple speeds, the owner is able to increase or decrease the CFM to the rooms. We've never heard the complaint that there's too much air exchange.

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