Final piece of the puzzle with respect to the ventilation system is Co2 sensing so I can drive the HRV at the 55, 65, 75 or 90 CFM configurations (or off completely) depending on real time air quality in the home. To that end, I ordered up these two items, the Ecowitt G1100 gateway and Ecowitt WH45 air quality sensor. These are powered by USB (they don't include the wall wart, just the USB cable. They are not super expensive about $150 for the pair. Turns out our air quality in our home is quite good with PM 2.5 and PM 10 levels at 0.1...which is very low. Those two are measurements of particles in the air, where PM 2.5 are of particular concern as they can reach your blood stream via inhalation. These particles are small enough to travel all the way through your lungs to the alveoli where gas transfer is taking place.
The G1100 WIFI gateway connects to your home WIFI and then their sensor devices (many can be added including outdoor weather stations, soil moisture sensors, etc) connect to the same gateway via 915 Mhz radio. The gateway has a built in web server to display data so the system does not require an app, cloud account etc. to operate. More importantly, it can send data to the Hubitat automation hub. Specifically Co2 levels are sent every minute or so, which in term now drive the HRV system depending on levels of Co2 detected.
There is a very nice integration written for Hubitat which is 100% local code, no cloud accounts required. The integration is maintained currently by @sburke781 who has a done a great job with it. The G1100 gateway sends data to the Hubitat hub every 60 seconds. It was a bit of a process to get everything set up but has been rock solid since installation.
I was tipped off on an issue with my older Co2 sensor which had automatically calibrated itself to inside air and was reading nearly 350 PPM low. I had to factory reset it, and it now reads very close to the Ecowitt WH45.
This is what the live data feed looks like from the G1100 gateway's built in internal web server:
The gateway is very compact and like the WH45 is powered by USB. The WH45 can also run off two AA batteries installed in the base, but reports less frequently when run this way. You can view the live data via an app (free cloud account required) or via the internal web server on the gateway. I purchased these after reading all the great reviews by users here on the forum.
