Panasonic Intelli-Balance ERV notes

FV-10VEC1, FV-10VE1, FV-10VEC2, FV-10VE2

I have the VEC1, looks like VEC2 is out with the addition of a boost switch. Otherwise it’s probably the same.

Here’s my notes on getting it as smart as possible based on the units quirks. I hope this is helpful to others.

  • Device monitoring is done with Sonoff S31 smart plug with esphome firmware to do power monitoring. Custom template is added to fetch on/off status based on power usage
      friendly_name : "ERV Running"
      value_template: '{{ states("sensor.erv_ac_current") | float > 0.2 }}'
  • Simple 5V USB relay board from Amazon controls the “wall switch” dry contacts, also flashed with ESPHome. I used the Normally closed configuration such that should there be a failure, the ERV will just do it’s own thing (set runtime). If both occupants away, it disables ERV.

  • Note that a toggle of this relay will actually “restart” the ERV schedule. eg if you have the front knob set to 10 minute runtime, and the unit runs for 10 minutes and then stops running, toggling the relay will cause the unit to start another 10 minute cycle immediately.

  • Automation could be done such that when the unit transitions from ON to OFF, and value X is still Y (eg CO2 still over 1000), toggle the relay which causes another cycle to run. (I use to monitor CO2)

  • Note that the front power switch is rather useless. When the unit is running, it will open the damper that blocks off outside air. If you turn off the front power switch (or unplug the unit alltogether), the damper will NOT close. The only way to stop a cycle and have the damper work is via the “wall switch” contacts. This is why a regular HA controlled power outlet is not a great option - turning the unit off mid-cycle will leave the damper open, undesirable in cold weather.

  • VEC2 could have a 2nd relay on the newly added boost terminals for VOC/CO2/etc sensors.


Hey there, @gcormier !!

I’ve been googling around looking for controls options for my intellibalance VEC2.

I wasn’t going to do any switches initially, but reading what you said and others too about the dampers not closing when typical power is cut, is problematic for me in our cold climate (I have the unit plugged into a smart switch to operate). I’d also like to get a boost switch so that we can run lower cfm 24/7 and boost when an IAQ monitor detects an event.

I’m not great with electrical, so are you using the 5V board as the “smart switch” for your HA automations? My biggest issue seems to be, if I want to use some sort of smart switch/relay, I need power from somewhere and since a dedicated switch was never wired in the first place from a circuit, I’m not sure where to get the power from.

I’m also curious if you’ve done anything else with this, since it’s a few years now.


I get the power with an outlet splitter and USB adapter.

I’m using this but there are tons of these style, just make sure you can flash it with esphome

MHCOZY WiFi Momentary Inching Self Locking Wireless Smart Switch Relay Module for Smart Home 5V 5V/12V

On top of co2home I now have GitHub - gcormier/espairqual to monitor my PM levels. I have multiple units inside my supply and return ducts that can help decide what to do (lots of forest fire smoke last summer when I actually turned off the ERV.). I also monitor my air handler delta-T and the ERV temperature with GitHub - gcormier/esptemp8c: 4-channel thermocouple logger using esphome - this is just for fun for the most part. The delta T let’s me know my AC is doing fine, the ERV fresh air temp was just me being curious at how effective the Panasonic exchanger is at taanfwrring energy between the air streams. I was pretty impressed in the winter we’ll see how it does when. It’s -30C outside :slight_smile:

1 Like

Thanks! I don’t know why, but I thought I needed to run a line and neutral to a relay switch, like a regular smart switch, but you are just powering it with a USB like any other small electronic device. Silly me, over complicating things.

@gcormier - Does the switch relay need to be “dry contact” ?

Great question - yes, it must be a mechanical relay.

I had initially tried controlling it directly from my Ecobee, which does not use mechanical relays but probably uses solid-state relays, and it did not work. The ERV was always enabled.