How to use HA to monitor six unit rental property for temp/humidity and flood detection?

I am relatively new to HA and am looking for some pointers to get started. I have a setup working at my house with the existing Wi-Fi based hardware and it’s really impressive. My parents have been battling some mold and flooding issues at their rental properties, and I see a potential for HA to be very useful for them.

Based in my experience with Wi-Fi based sensors, I do not believe that they will be reliable enough for this use case. I am looking for recommendations on sensors and protocol to use. I would prefer to keep as much hardware wired as possible, but I am not finding a lot of sensors that are wired.

The goals are:

  1. Monitor temperature and humidity within the units, crawl space, and attics.
  2. Be able to trigger “dehumidify” mode on a mini-split system.
  3. Monitor for water leaks in the laundry room, utility area, and crawl space.
  4. Monitor doors to the utility areas that should not be accessed by the tenants.
  5. Possibly monitor for smoke/CO. (We’re not sure we want to do this since HA is not a real monitored service like an alarm system.)

The layout:
There are three duplexes that are side-by-side. We have internet on site already and have a utility area in each building that we could locate hardware. I would like to have one HA controller for all three buildings. If needed, we can connect the three buildings with a network for this purpose. Each building is single story and about 1,500 square feet.

Property inspections occur once a year and batteries can be replaced at that time. I am looking for recommendations on the hardware sensors to approach this with that are better quality and more reliable for long term use. I have a preference for hard wired network/power, or POE, but it looks like most sensors are battery powered. That is okay, as long as they will easily last more than a year on a set of batteries.

I have not had personal experience with either Z-Wave or Zigbee, but based on reading I am leaning towards Z-Wave do to possibly better compatibility. I would not want to deal with running both, but I am interested in recommendations for one or the other.

What kind of hardware should I be looking at?

POE would be most reliable and of course no battery problem. You can build out POE wifi sensors with esphome.

An important consideration is how you activate your mini-split system, most are IR only which can be a bit of a pain but can of course be done. There are retail systems like Sensibo (I mention that one only as I have three and aside from being cloud based they are excellent). Of course most IR bridges are again wifi.


I would lean towards Zigbee, as chep Hue bulbs could be installed in common areas and they work as routers to extend the network. Sensor even report battery, so you could be alerted by HA if the are about to go dead.

I live in an about 150 squared meters house (elongated rectangle, about 8 meters wide). I have a Sonoff Zibgee Bridge running tasmota as Coordinator (Integrated to HA with ZHA) at the centre of the house and one hue bulb in the front and back rooms, that covers the whole area. Its a brick and mortar construction, thick walls.

I would install coordinator somewhere and bulbs to act as router scattered in common areas to create the whole nerwork.

Zigbee sensors are cheap and really easy to get. I currently have lots of Xiaomi Aqara temperature and door sensors, they work great… Testing some Sonoff ones now too.

None of the units have mini-splits now, so that is something to consider when we do the install. I personally do not like the IR sensors and would want something mounted on the wall like a traditional thermostat.

I went down a rabbit hole yesterday researching Zigbee and Z-Wave. Z-Wave seemed a lot less stable than I was initially interpreting it to be. It appears that integrating a Z-Wave hub connected to the same network as HA is not as easy as it first seemed. Having three of them looks a lot harder.

Does Zigbee have these same shortcomings? Does anyone use Hubitat in combination with HA? It almost looks like Hubitat would do everything we’re using HA for in this instance.

Went down the rabbit hole? Then you might have found me… got lost in it months ago.

I would direct you to these two youtube videos about the different networks, they can explain it better than me and offer some comparisons.

I can only speak about my experience with Zigbee and Home Assistant (haven’t even tried Hubitat).

My network, as I described it in my other post, is extremely stable and reliable, had some issues with a single temperature sensor that is about 15 meters from the Coordinator (about 5 brick walls in the middle) before I had the hue bulb in a room about half way acting as a router. After that it never lost connection ever again.

Zigbee could get you covered for temperature, humidity, flood (water leak and access to restricted areas. There are both zigbee and RF433 smoke detectors.

RF433 has a greater range, but kind of old technology, sensor are not as “smart” as other options, but you have also every sensor you require. You would need another “coordinator”. I also run a Sonoff RF Bridge with tasmota and Portisch for this protocol.

Item 2 of your list, that’s a real rabbit hole… I would consider some wifi enabled mini-split systems. I know there’s a HACS for Midea ones, and I think Samsung too, that would eliminate the need for IR. You’ll have to google the s**t out of this. If you somehow get some kind of minisplit with wall mounted panel (never seen one, but hey, I live in a third world country xD), and that can be replaced or triggered by dry contact relay, then it’s an easy fix (I have a something like this controlling my gas boiler).

Sorry, I talk too much, even when typing.



Just my personal experience, my Z-Wave devices are the most problematic while the WiFi devices have yet to fail. The only Zigbee devices I’ve used are Ikea lights. Garbage. (At least the Ikea hub). I’ve only recently added some 433mHz water alarms in the basement and bathrooms. Using the Sonoff RF bridge to connect to Home Assistant- they have all been reliable.

Thanks @jcasarini, those videos were pretty helpful, but now want me to wait for Matter to come out!

This is a bummer. I have been having a lot of trouble with my WiFi devices dropping offline for 5-10 minutes at a time. I have really good WiFi throughout my house and don’t have any issues with other computers, printers, etc. The devices I have are mostly Kasa plugs and light switches. The Phillips Hue bulbs we have seem to be pretty stable. Maybe it’s just a Kasa thing and not a WiFi thing?

Since this will be set and forget, it needs to be solid. I suppose 5-10 minute drops would be fine as long as they come back. This is more for long-term monitoring to combat mold problems when tenants let the conditions get too humid inside.

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When it comes to mini splits, rarely are there heads installed in these locations. While activating a whole home dehumidifier will help, it 's far from ideal. Localized dehumidifiers or exhaust fans are probably better choices.

Access control I use these, they are not smart. They are cheap and vandalism resistant. Adding an esp to it shouldn’t be too hard.

Those are cool. I don’t think we need that big of a deterrent. There is already a lock on the door and I can just use a door contact sensor to detect when they are opened. Someone must have a key because they keep turning the hot water up to scalding temperatures and then the other unit complains. This is just to detect the door has been opened and send an email to the property manager so she can check on it.

Those are just the areas I want to monitor in general. The mini-split will be (it’s not installed yet) in the center of the unit’s living area. The tenants have a tendency to turn off the heat in the winter to save money and we want to make sure that pipes don’t freeze and we keep the humidity low enough mold doesn’t start (mold is a big issue now).

Philips Hue bulbs AFAIK are Zigbee, not WiFi. Philips Wiz bulbs are WiFi.

I have an assortment of Hue (zigbee, not using the hue bridge, paired them with the tasmotized sonoff zb brigde), Wiz (not Philips brand here) and Yeelight (both WiFi) lamps.

Everything is very stable, even Wiz lights that are not officially supported by HA yet, running then with a HACS.

I don’t envy your situation a bit… because one you choose and marry to one network, it will be very difficult to switch.

How do you want to respond to this situation, will you notify the tenant or do you want the system to turn the heat on?

If you need to control the unit, then which brand you choose will determine if you need wifi/zigbee/zwave. There are plenty of bulbs and sensors for all the protocols.

Response would be an email to the property manager if we approach critical temperatures. Otherwise it’s more long term trend monitoring for humidity that is conducive to mold formation, and then activate the dehumidifier mode of the mini-split and/or email the property manager.

I think at this point I am going to buy some Z-Wave hardware to test at my house. I think we have about six more months before the next scheduled walk through so I have some time to test.

How I am reading everything though is that I’ll need a USB stick to work with HA. I can’t get a wired network hub for each building and tie all three into HA, correct?

This is my worry! I do have time to test, but when deployed we need it to be reliable. I don’t have a lot of time to be fiddling to keep everything working.

Matter really looks to be the right solution, but it’s not available yet.

May be a bit more expensive, but… why not a HA on an RPi for each building, and a smartthings hub + smarthings temp / humidity sensors as needed. Then you can join all the HAs into a single UI if I’m mistaken using GitHub - custom-components/remote_homeassistant: Links multiple home-assistant instances together

I could do this if needed. We are adding a small wall-mounted network rack in the middle building with a NVR for some security cameras. It would be easy to throw in a small 1U fanless system of some sort to run HAOS on. That’s what I am doing at my house to play around with it, it’s just one of three lightweight VMs running on an ESXi box.

Question: Can HA handle more than one Z-Wave or Zigbee dongle at a time?

What if I used one plugged directly into the system, and then two of something like this to connect a dongle from each of the other buildings over the network?

I have a z-wave dongle running on my home assistant server with home assistant running a a virtual machine on ubuntu 20.04. With zwave-js the system just works. I have about 14 battery operated water sensors spread all over the house.

Z-wave is generally slightly more expensive than zigbee as z-wave is proprietary.

I use fibaro leak sensors. They can be run by a 12vdc power supply. They also can have extension wires so the puck can be mounted on the wall near power and the extension run to the potential leak zone.

here is a link to the manual.

Edit - I was wondering why you think you need multiple systems? If the renters are not going to interact with the system then creating areas such as Unit1 - Bathroom, Unit1 - kitchen, unit 2 - kitchen would let you have them all in one system. You might need z-wave or zigbee boosters in each unit but manage via single unit. just a brain fart on my part. The extenders can reach about 300 ft

Get an Elk M1. It will work reliably regardless of the state of your HA controller and there is an excellent HA module for it.

The only question is controlling the mini-split, if it will take a normal thermostat then the Elk should work. There are wired and wireless sensors for everything else on your list. Also using a UL listed alarm system can bring discounts on your insurance, so it may pay for itself.

Can’t speak about Zwave… but there can only exist one Zigbee Coordinator in your config… Maybe two if you use different integrations for each one (one with ZHA, another with Zigbee2MQTT), but the setup and maintenance for that would be a hassle.

You can have single coordinator, but a lot of “routers” scattered to increase the range of the network, I tried a CC2351 USB dongle (first use as coordinator, then flashed as a router), but ultimately the Hue Bulbs where the big winners there.

You could do BLE also, there is several models of sensors available inkbird, qingping, xiaomi with even the possibility to update the sensor firmware (lywsd03mmc).
The gateway could be an esp32 with an external antenna to get a good range (one per building).

Also you could consider Lorawan (for the range) with a single gateway, we can find a variety of sensors now. But we are a little bit at the limit of the world of home automation and more on the iot/professional side.