Would appreciate any recent comments on accessibility of the Nest (low end, not the Learning Thermostat) and Honeywell thermostats for totally blind users. Specifically,
1) How is the accessibility on their iOS apps?
2) Can you control these apps with Siri? with Alexa?
3) Do the apps allow you to control the AC/Heat fan?
Not sure which one it is, but the Nest I have is completely accessible through the app. Not only that, once you get an idea what the temperature on the thermostat is, you can feel it click when you move the actual thermostat dial so in case your internet is out for some reason you can still make adjustments as far as the range. Not sure what you'd do if you were trying to change from heat to cool or vise versa.
I don't know about the Nest or Honeywell devices, but I had an ecobee4 installed in my home, and I find the iOS app quite accessible. Admittedly, dragging the temperature up or down on the app is a little irritating, as it doesn't read as it moves, but the app is mostly accessible via Siri and/or HomeKit.
It has a remote sensor you can place in other parts of the house, and it will monitor temperature. You can pair more sensors with the thermostat also. For example, I can ask Siri what the temp is in my office, and she'll tell me that room specifically. If I tell her to cool the bedroom to a certain temp, the thermostat will run until that room reaches the desired temp.
The thermostat itself is not accessible, though it does have Alexa built in, which I do not use.
This thermostat is also accessible via their website.
My overall opinion is it's mostly accessible, though 99% of the time, I'm telling Siri to operate it. Turn AC or heat on or off, asking for temp or humidity in a given room, etc. The only thing I haven't been able to do with Siri is turn on the fan to circulate air, but this can be done in the app in the quick changes menu.
It helps that my local utility company did an energy evaluation, and installed the $250 device for free. I had to pay for extra sensors myself for around $80 for 2 from Amazon.
I am an owner of the Honeywell Round 2.0. The Honeywell app is completely accessible. It does work with home kit (Siri), but you have to have a C wire to set up any home kit device as far as I am aware. Apple has a list of home kit compatible devices on their website. I was also looking at the Honeywell Color before I purchased the Round, but it is not integrated with home kit, just Alexa. You can control the heat fan, cool and hot air. Most homes have a single stage HVAC, but if you have a multistage system, you may want to look at the Honeywell t6 pro. I did not realize that the nest and Echo apps were accessible, otherwise I would've considered those as well. I found publicly available information lacking in this area.