I'm going to install an manometer to learn more about the pressure drop across my HVAC filters, and more accurately determine when the filter really needs to be changed.
I cannot find any low pressure manometers that are zigbee or zwave. Thus, at this point, I think I will simply install something like the Dwyer Mark II and manually read it, but before I pull the trigger I would love to hear any ideas y'all have on a different device that could be monitored vai the Hubitat, or even just alert the HE when it reaches a predefined pressure drop.
I don't know if this would be accurate enough but you could try a ESP32/ESP8266 running Tasmota with two BME280 sensors, one on each side of the filter, connected to hubitat via wifi.
The BME280's read barometric pressure, temp and humidity. Combined with Tasmota sync drivers to connect Tasmota to hubitat.
I did find this "Clickboard" thing that offers both manometers and zigbee modules, but again, I have no idea a) how to put them together and power them and b) how to get a Hubitat driver to actually read the manometer results.
Based on one of the above comments, I'm wondering if my Aqara Temp/Humid/Pressure sensors are accurate enough for this. I doubt they are but it is worth a try. Thanks to the generosity of @tedrpi I have two of those used for humidity monitoring.
I'm also wondering if there is a way to use one of the Homeseer HS-FS100-L indicator light sensor to connect a standard manometer to Hubitat. I looked at some monitors intended to ensure a radon system is operational, but I think they simply measure air movement vs no air movement. Ideally, if I could figure out how to trigger an HS-FS100-L when the liquid in a U tube manometer gets to a certain level, that would be ideal; the manometer would work without power and without Hubitat, and Hubitat could still send a notification via the HS-FS100-L.
I have a Aqara THP sensor and I put my mouth over it and blew into it the pressure rose from 984 to 1047 after a few seconds and then dropped back to 984 hpa so it's worth a try as it responded quickly. The actual numbers aren't important, the change in differential over time (new v. used filter) is what is.
I use BME280's in my Home Assistant instance to track temperature and humidity (imho they are way more reliable than DHT22's). And while I've known the BME280s track pressure, I never paid attention to that metric lol.
Have you actually tried putting it in your HVAC? I wonder whether it would hold up in that environment (granted, they are cheap so it's more about not wasting the effort than it is about the $$$). And I also wonder whether the BME280's resolution/precision of the pressure metric is sufficient to monitor filter performance?
Are you talking about AIR Filter monitoring with differential manometer?
For my quriocity what pressure drop do you expect for dirty filter?
My good guess, filter must be very dirty in order to catch a detectable pressure drop.
PS.
When I lived in a house I had a DIY "Whole House Water Filter Monitor" based on measuring pressure drop across the filter. This worked wery well. But I didn't think this technique will be relible for the Air Filter monitoring (unless everything is wery well sealed and differential pressure gage is extremely sensitive).
Lots and lots to read on the internet about using this kind of device to measure the drop in water column. Too many factors to consider and there is no exact answer for all systems on what the drop might be when you want to change the filter. Ultimately, you could get an HVAC person to run the calculations etc. Or you could calibrate with a new filter and a filter you think is at the point where you like to change it. Mark the device with a sharpy. Done.
That is exactly my point.
I like to automate everything. But monitoring HVAC Air Filter is not considering at all because the result is similar to flipping a coin. Some sort of photometer may produce much better results vs measuring diff pressure.
