TL;DR: Superb switch, supports Matter over Thread and Zigbee. I added it directly to Home Assistant using Matter over Thread. I did not use Aqara's app and I have not used Zigbee, so cannot comment on this aspect. You will need a Thread Border Router/Zigbee hub, which is clearly stated. I was unable to set minimum brightness in Home Assistant, but this can be done directly on the switch.
I have a Home Assistant setup and was using an old WiFi based smart dimmer that I had flashed from Tuya->ESPHome. This original dimmer was my first foray into a connected home and what made sense then, no longer works for me. The first thing to note is that I went for form over function and ended up with something with touch sensitive buttons and looked great, but actually did not work particularly well. For instance. Turning the light on/off took about 5 seconds with a very nice fade in/out effect, which looks good, but became irritating very quickly. Also, it has none tactile touch buttons to change the brightness, which again looks cool, but becomes old very very quickly. Also, the switch is leading edge triggered and only works well with incandescent bulbs, which do not last long, are expensive to run and bulbs are getting harder to find and increasingly expensive.
So when the last bulb went, it was time to replace the switch. When looking, I wanted a switch that was more like a traditional dimmer - e.g. a push button and dial to set the brightness. Next I wanted some that works with LED dimmable bulbs. Lastly, I ideally wanted something that uses Matter over Thread, or Zigbee as a plan B. I actively avoid WiFi based devices (including Matter over WiFi), as I have found WiFi not to be particularly good for IoT for a number of reason I don't need to get into here.
Enter the Aqara Dimmer H2. I have a number of Aqara devices already, so I was confident about the quality and it did not disappoint in this respect. The switch is chunky, well made, reassuringly weighty and looks great. It also ticked all of my boxes with a chunky dial/push switch, works with LEDS and also support Matter over Thread and Zigbee. The only downside is that it's comparatively expensive, but Thread is not well established yet, so this is to be expected and certainly what I am seeing with other Thread devices.
Fitting the switch was really easy. The instructions are clear and the switch slides nicely into place. the only concern I had was that it is quite a deep switch, so consider the back box depth when buying. That stated, the centre mass has a comparatively small diameter, which leaves plenty of room to route cables around the edges. Another thing to be aware of is due to the way the switch is mounted in the back box it is not possible to twist the switch to true it up, so if your back box is not level, the switch will not be either.
Reading through the reviews, it seemed that the switch had to be added to the Aqara app first (which is a white labelled version of Tuya/Smart Life) and then added to Home Assistant. This was not the case for me and I was able to add it directly to HA with no problems at all. As a side note here, the QR code is printed directly on the front of the switch, under the facia, which demonstrates the thought that went into the design and avoids the need to store a random piece of paper in case I need it in the future.
Once added to HA the switch popped up like any other switch and worked seamlessly. I quickly realised that with the bulb I was using, I needed to change the minimum level as the bulbs lower limit was 55%. This is not available in HA and reading around, my heart sank when there was more than one comment that this can only be done on the Aqara app. I started to add it as a secondary connection, but quickly gave up when I realised that I don't have a Thread Border Router added to the app. Anyway, long story short, I read the manual and found that I could set the minimum brightness directly in the switch, which was a huge win.
As an additional plus, it includes power monitoring, which is not currently in my list of must haves, but something I am increasingly thinking about when buying new devices.
The result is that I am very pleased with the switch and definitely will be replacing all of my other dimmer switches in the next few months.
