Smart Thermostat Recommendations for 2021

I’m sure this has been discussed, but I didn’t find what I was looking for using the search function.

I’m new to home automations, and seeking the best hardware for my desired setup. I’m currently looking for advice on a smart thermostat that DOES NOT require internet connection for local LAN access.

I’d like to be able to use an app on multiple devices (tablet, phone, and/or PC) on my LAN to adjust thermostat settings, and I’d like to leave the internet out of it.

I’ve been eyeballing the EcoBee, but from what I’ve read it says it requires a connection to the internet.

For devices that do NOT require Internet cloud access, the Zigbee & Z-Wave standards are designed for local mesh network connection with no Internet access needed.

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Thank you for the reply and input. I’ve done a fair amount of research and homework on the Zigbee and Z-wave networks over the past few hours, and I’m still not convinced to use it over WiFi.

Do most WiFi devices inherently require a connection to a cloud-based server and not permit a local-traffic only functionality?

Thanks in advance!

Z Wave and Zigbee aren’t wifi in the traditional sense. They are local only networks that you can use on a local wifi network. Somehow you have to get the signal from the phone to the device, like a light. This works by using a hub like Homeassistant on a Raspberry Pi and having the phone and the RPi be on the same network, you could pull your WAN connection and everything would still work…

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When I started home automation i wanted local access too. Being a Wi-Fi engineer I know the 2.4GHz wireless space used by all smart home Wi-Fi devices is inherently prone to interference from all sorts of devices, including microwave ovens. I ended up buying a combo zigbee / z-wave stick for the US and tried Z-Wave. I have not pursued Zigbee or Wi-fi beyond the Amazon plug I was given as a gift.

An overseas developer friend who develops automation software for both Zigbee and Z-Wave for home and commercial customers prefers Zigbee. He has even had some of his commercial software officially Zigbee certified by passing their expensive certification testing suites. I do notice Zigbee devices tend to be less expensive than Z-Wave. Z-Wave devices are divided into incompatible world regions. I have had poor experiences with cheap Chinese made Z-Wave sensor devices.

Most all Wi-Fi devices, as sold by the vendors, require access to their proprietary cloud servers, Some people have built their own thermostats using ESPHome but I am not that adventurous.

With ecobee, there’s another route you can try: via HomeKit (the protocol).
Since it is HomeKit, communications and at least basic controls would be local. However this is rather convoluted and thus not for everyone.

  1. Set ecobee to pair via HomeKit, to one of those HomeKit hubs by Apple (iPad, apple TV, etc.) This is temporary.
  2. From the HomeKit app, remove ecobee from Apple’s HomeKit garden, so that to force the ecobee into a “hey I’m a HomeKit device, any HomeKit hub out there wishing to pair with me?” status.
  3. Setup your HA with the integration " HomeKit Controller", so that to make your HA instance a (non-apple) HomeKit hub
    (The “ecobee” integration is not what you are looking for. It works, and works great, but not local.)
  4. Now pair the ecobee with HA via the “HomeKit Controller” integration. HA should now pull ecobee into its fold.
    (Do not use the other “HomeKit” integration, which is to push what you have inside HA into another HomeKit hub from Apple, and thus not what you want)

Now, your HA should be able to talk to the ecobee via HomeKit (the protocol). The ecobee unit itself would still talk to ecobee cloud, to get weather data to display on the ecobee unit, for example, but at least HA gets to control the thermostat locally, even when your internet is down.

There you go. As I said, rather convoluted and thus not for everyone.


So, I wasn’t completely sold on Z-Wave, but now that’s the direction I’m leaning. I have an ESXi server that runs 24/7, so I was gonna run one of the VMWare workstation images.

This raises 2 questions:

1: What is the best, most headache-free and reliable way to connect Z-Wave to my VMWare image?
2: Is this Honeywell Z Wave thermostat a good option for something that works like a normal old thermostat, but has Z Wave functionality?

Additionally, it would be nice to have controls for a humidifier (or other HVAC functions), and I don’t see that this t-stat has built-in functions for such things… ?

If you want something that is relatively cheap and can be on 24/7 why not go with the Raspberry Pi option?

Its very small, low power draw, on 24/7 and works very well with a HA flashed SD card. Integrations are very easy and its accessible on the local network…

I guess it’s because I don’t currently have a modern RPi, but I do have an ESXi server that already runs 24/7 hosting multiple other services to my house.

The Venstar T7900 has a local API and HA support. It’s working quite well for me.

Always interested with Ecobee-HomeKit recommendations. May I ask:

  • How does it pull Ecobee current preset mode, HVAC mode, fan status?
  • How does it set Ecobee into a preset mode?

I found these are not implemented, with many other useful HA service calls.

The only thing I can do with HomeKit is setting the thermostat back to following it’s original schedule. Ecobee integration has all the features I need but it sucks in (1) requires Ecobee WAN service and (2) random lag.

Bought this today. Do use any temperature sensors? The Venstar ones compatable with the thermostat are insanely expensive (~$150).