It really really depends on what you have for heating.

Floor heating + heat pump? You don’t need to mess around with target temp much because the principle behind it is thermal mass buildup and maintaining that. You have to tune thermostatic valves on the room level. Then you can have one central thermostat simply slightly change the target temperature with many hours of delay. That doesn’t seem too useful to me to automate.

Do you have radiators? Then you can get zwave or ZigBee valves and tie them together with whatever thermostat that you want in home assistant. Then you can set per room/zone heat depending on whatever sensors you have.

Do you have central forced air heating and air conditioning? Then you have pretty much target temp and on/off control unless you want to put in motorized automatic registers or redesign your entire duct system for per-room duct valves.

Individual heat pumps/airco units with radiator based heating is the most “per room” customizable and probably the most useful to put automations on in Home Assistant.

Ventilation can be useful by monitoring CO2 levels and humidity. Then you can use either the fan units themselves or socket switches to actuate those and put whatever sensors you want wherever it is useful.

I am probably missing some stuff here, but there are only a few HVAC setups that actually benefit from automation, in my opinion. Mainly ventilation, infrared, and non centralized forced air heat pumps. Plus heating and cooling is something you want to work 100% flawlessly even if your router dies, your home assistant falls off a cliff, and your ZigBee/zwave controller dies.

Feel free to ask over at [email protected] too.

But to echo some other comments here, whatever you do, keep it simple and ensure a botched HA update doesn’t freeze / cook you by using standard components as a backup / failsafe

Best place to start would be to look at the thermostat hardware you’ve currently got, and start searching online if anyone has integrated it into Home Assistant.

I’ve lived at a few houses now with Home Assistant. In all of them I was able to integrate my HVAC and automate it, but some brands and hardware are definitely easier than others.

I think the most extreme of them required a custom esphome device connected to its PCB to talk to Home Assistant, and another required me to write my own custom component.

Hardware and brands make a huge difference, but sometimes you’re stuck with what you’ve got.

I have a cheap homekit thermostat that I use with home assistant. Being able to turn it off for movies or during peak energy hours is nice. What was most helpful, however, was putting temperature and humidity sensors in every room, so that I could move around heat generating stuff to balance the temps throughout my apartment. I moved my server and gaming pc tower out of my home office. The temperature spread went from 8 deg F to 2 deg F.

I have ESP8266 WiFi modules running Tasmota firmware for a few parts of this. Some report temperature (and humidity just for fun), I like DS18B20 sensors better than SHT30s which seem to have a bit more self heating. Then I also have Mitsubishi mini split heat pumps for which there’s a Tasmota control library. MQTT for communication + HomeAssistant for UI + AppDaemon for automation scripts in Python.

Examples of the UI in HA:

Each room has one ZigBee thermometer and thermovalves for the heaters. Home Assistant with an automation open and closes them based on the thermometers.

Also in HA, I have a schedule for the “comfort” temperature so that the boiler can be turned on and off accordingly.

See https://wiki.gardiol.org/doku.php?id=homeautomation%3Aheating for the detailed setup.

Zigbee or Zwave temperature/humidity sensors are common. Add a 3-circuit relay box and you can simulate the behavior of pretty much any thermostat with a few rules.

HA or any other system that can toggle outputs based on sensor thresholds would work just fine.

there are some subtleties with real HVAC thermostats, like running your AC compressor at least five minutes and ensuring that it stays off for at least 5 minutes when it’s turned off.

I got a Venstar T2000. Its at a decent price point, HAOS has built in support for it, and it can work entirely without internet.

FritzBox Dect.
Minimal networking footprint utilizing Dect as the transmission protocol.

I have a cheap ZigBee thermostat and some automations to control temp. Works ok, but I’m trying to smarten it up a bit in the next few weeks.

I’ve got a couple Honeywell T6 z-wave thermostats that work great and didn’t cost a lot. I control them through home assistant with some custom code to set them on a schedule, but they can also still be operated manually if needed.

I live in an apartment building with a stable enough temperature that I never have to use a heater or AC, but I do have a number of zigbee temperature/humidity sensors and a Home Assistant automation that turns on a window fan if the relative indoor vs outdoor conditions are favorable.