homeassistant

Recently was given an Ecobee smart thermostat. Ecobee does not have a great integration for Home Assistant, but Home Assistant can act like an Apple HomeKit hub, and if you provision the smart thermostat through that, it is entirely local.

Just switched to a Honeywell T6 Zwave (model TH6320ZW2003) thermostat and really like it. It's a big step up from my old wifi thermostat. There are some nice features like a humidity sensor and adjustable backlight, but the feature we like best is the Circulation fan mode that runs the furnace fan a certain percentage of the time even if the system isn't heating or cooling. This has made a significant different in our comfort level and we notice when the fan isn't set to Circulation.

Since it's locally controlled, settings changes take effect immediately without the delay we regularly had with our old wifi Honeywell. Programming was more involved than a regular smart thermostat, but not overwhelming. It can be powered by a C wire or by batteries. Ebay has open box, like new models.

Honeywell T6 Z-Wave

I'm using it with an HA Yellow with a Z-Wave radio. It's flawless. I don't know if it can be adapted for 2 wires but it definitely works with batteries.

You're going to hampered in your choices by the lack of wires. You have an old 2 wire setup. Most nowadays want 3. Some can handle 2 wires, look for thermostats that don't need a "c wire" or "control wire".

This suggestion depends on your skill level and desire to be completely free of corporate bs.

The ‘smart’ is already in home assistant. You do not need a smart thermostat at all. Instead you need temperature/humidity sensors and actuators for your HVAC system. There are several decent smart climate control integrations already and a library for PID control if you want to make your own control automations.

Of all the smart things out there, a thermostat is completely unnecessary. The only solid reason to buy one is convenience, if one is just not into thinking about it too much.

If privacy and autonomy are a priority, however, this is low-hanging fruit to declare independence from corporates who like to rummage through your underwear drawer.

I looked into this a few years ago. At that time, if you had a "c wire", there were several options that would work directly with HA.

I don't have a C Wire so that didn't help me.

Without a c wire, I was only able to find a single option. A "Sensi" brand that could run on batteries, but wouldn't work directly with HA. Tou had to control it though Amazon Alexa or through their app. Neither option turned out to be particularly reliable.

Where do you live? What type of unit do you have?

I just got the Meross Smart thermostat running. (The installer literally just left 10 minutes ago.) I had to call an HVAC person to help me install it because I didn't have the wiring setup properly for a wifi thermostat.

Maybe call an HVAC company and tell them you want to install a smart thermostat, but you're unsure if your system is compatible. (Maybe they can do some HVAC maintenance while they're in there too.)

An ESP8266 running ESPHome and a relay would work here. It's basically on or off. Then you could pull temperature information in from multiple temp sensors around your home.

I do something similar for some solar air heaters I built.

We (UK) recently put in a Tado X thermostat, which uses Matter over WiFi - as soon as I work out how to setup Matter server in a docker, I'm hoping that will connect with HA 🤞🤞🤞

Depending on your comfort level, you may want to do what I'm in the process of doing. I'm still waiting on parts, but this will work for my heating system.

I have old 2 wire thermostats in a few places I want to replace. I have hot water baseboard heat with multiple heating zones. I couldn't find an existing solution that worked the way I wanted and was reasonably priced, so I decided to make my own. This only works for single stage systems and for which exhaust fans, circulation pumps, or other components are controlled by the heating system generally and not by a single specific thermostat, which if you have those old mechanical 2 wire thermostats is almost certainty the case. You could do more sophisticated, but I don't need to.

All I need is a relay (controlled by HA) to simulate the thermostat turning on/off. I also need some way to tell it when to turn it on/off (such as a temp sensor), again lots of options with HA.

This can be done in a variety of ways, but I'm using nodemcu boards (they have wifi onboard) and esphome firmware. I've used this combination for a number of HA integrations so far. Near my boiler where all of the old thermostats connect will be a nodemcu board with multiple independently controlled relays (for each thermostat to control the individual heating zones).

The 2 wires that go to my old thermostats will be power supply for separate nodemcu boards, which will be in a 3d printed case along with buttons, display, and (in one room) will also include a temp/humidity sensor since I don't already have one there. The other locations already have more sophisticated air quality sensors that include temp/humidity, so no need to duplicate, although maybe I will for redundancy.

I purchased a tado X recently for this because I wanted matter. However, this is a highly overpriced item for the result and in my opinion not really worth it. I've read the Honeywell T6's are really good. 👌🏼