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Share Your ERV Setup

dennis_vab | Posted in Mechanicals on

I’m interested in hearing and seeing your whole house ventilation system. If you have pictures please include them.

-HRV/ERV brand
-How you control it
-IAQ Monitors
-Material used for air supply
-anything else.

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  1. user-5946022 | | #1

    1. Panasonic
    2. Only controls are the controls on the unit and the breakers
    3. Airthings, but it is not interconnected to the ERV
    4. From the ERV, 4" hard duct to within 1' or so of the soffit terminations, at which point both supply and exhaust turn to high quality flex duct
    a. would like to learn a better way to control the units I already have
    b. wish I had been more aware of the details when these were installed - they "insulated" the supply with loose fitting bubble wrap "insulation". So I have cold air getting sucked through a conditioned space to the ERV. The supply duct distance is about 25'; the exhaust duct distance is only about 10'
    c. Exhaust terminations - I was able to install Panasonic EZ vents (that have an internal damper) in the exhaust terminations. I added insect screen directly on the backside of the grill piece. These were spec'd to be installed and should be installed prior to soffit, but they ignored that. If I had to do it over I would require hard duct all the way to the connection to the EZ vent.
    d. Supply terminations - They did not install any damper at the exterior of the supply. They ran from the ERV to near the soffit, then transitioned to flex duct termination turns directly over the soffit. They ran the flex duct past the underside of the soffit, then spray foamed the area. The spray foam deformed the flex duct a bit when it cured. Thus, the turns (90's that turn down and sideways) and flex are forever deformed. Then they installed the Hardie soffit, further deforming the end of the flex duct. All of this resulted in no way to get any sort of damper into this system without cutting out interior ceiling, which is not happening. The duct is so deformed there is no way to even get a 4" termination into the flex. If I had to do it over I would require them to run hard duct the entire length, and position the duct so that a Tamarack cape backdraft damper could be installed vertically directly over the vent so it is accessible.

    1. dennis_vab | | #3

      Thanks for your reply! How many occupants do you have, and what is the sq ft of your home. I’m guessing to have the intelli-balance 100 cfm ERV? Is the actual ERV installed in the attic as well?

  2. this_page_left_blank | | #2

    -Zehnder (CA550 model)
    -Programmed timer control as supplied with ERV, plus feedback from two CO2 controllers, one in the main living area and one in the master bedroom. Boosts the ventilation if the CO2 gets over 800ppm.
    -Only other monitor I have is a Dylos particle counter, which is not a continuous monitor.
    -Main supply and exhaust is 6" EPS tubing. Delivered and returned air each go to a manifold via 6" EPS and a short run of 6" flex duct (for noise isolation). From the manifold it's 2.5" ID smooth-walll plastic tubing to 11 locations (6 supply, 5 return), all home runs. Most locations are twinned, two are singles and two are triples. Triples are in the main bathroom and the kitchen.

    Regrets are not running a few more tubes, and it would be nice to be able to redirect ventilation at different times of day. Overnight, no one is downstairs, and during the day very little time is spent upstairs. I also have a ground loop pre-heater, pre-cooler. I control that based on the incoming air temperature. This works perfectly in the winter. In the summer, it would be nice if it could take humidity into account as well. The ERV has a "nighttime cooling bypass" feature, but I find that it really only works well if the unit is an HRV. With an ERV, even if the outside air is below the desired indoor temperature, bypassing the core is a bad idea if the outdoor humidity is high.

    1. dennis_vab | | #4

      Thanks for the reply Trevor! I would love a Zehnder Unit. I was quoted the Q350 model for my 2,600 sq ft home in Upstate NY, climate zone 6. Very expensive, although I’ll admit I haven’t compared a full comparison with another unit. I am giving some thought to a Broan HE unit as well.

  3. Expert Member
    Akos | | #5

    I have a Vanee 70E ECM ERV. Stale air pickups in the bedrooms and bathroom with the fresh air delivered near the peak of the ceiling in the living space. The fresh air supply ducting is all semi rigid aluminum, stale air are standard flex duct.

    There is an inline MERV13 filter box followed by a HEPA filter on the fresh air supply. With the unit running unbalanced to pressurize the house slightly it does a pretty good job of keeping allergy symptoms at bay.

    The things I would change:
    -unit does exhaust only for defrost, not very energy efficient, get one with recirculating defrost
    -recovery efficiency is not that great, you can really feel the chill on the fresh air supply on the cold winter days. Latent recovery is not that great so it dries out the place a bit too much in the winter.
    -the MERV13 filter is after the unit, I will eventually re-plumb this to put it on the fresh air intake to keep the core cleaner, the stock washable filter doesn't do all that much.

    I run a PLC for controls, but really the only thing you need for these is a simple timer switch for running them on boost. When cooking I find this needs to be about 3h to bring the pm2.5 back to baseline. Wet dog smell also seems to be about a 3h run.

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