Some ideas for temperature sensing and load switching needed - for a new guy

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Hello.

Am somewhat new to the Home Assistant topic, and would appreciate if someone can give me some thoughts about the following:

I am debating on buying the Home Assist Green device, and wonder what else I need for my first scenario (where I want to stay as offline, far away from Google and similar providers as possible):

I need to sense temperature (probe on a wire, not within a wall-mounted device) in a distant area of the house. Depending on the read of the temperature I need to switch an AC device in the same area. So in this case one device which can accept a wired temp sensor, and switch an AC load would be optimal. I have AC power at this spot, and very limited space.

I would love to have a very simple input/control option for this thermostat. In this case it could be (if a viable option) a touchscreen wired to the home assist green, or a separate controller on the wall, looking like a classic room thermostat, where I can set temperature and heat/cool).

I assume from the software side I could use:

But what are the options for the temperature sensor and the AC load switching? A Shelly device?

Maybe a Shelly 1PM Gen4, and a Shelly Plus Add-on - or something totally different?

I am OK with either implementing Wifi, or Zigbee. Distance about 30 feet, but two massive stone walls in between.

Would be great to get some thoughts/ideas.

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Hi,
There’s two main options:

  • Local control - e.g. Sonoff TH16 with a plug-in DS18B20 probe
  • Central control - e.g. Zigbee/Z-Wave/WLAN/other relay and sensor

For simple ON/OFF control, local works well. Standard Sonoff firmware can’t do local control (looks like some of the latest kit can), but Tasmota firmware (local rules) or Shelly devices can.

ESPhome can get more fancy with PID control and PWM control of resistive heaters.

If you need more sensors (more than one area), or more automation (more rules), a HA automation or blueprints like the Generic thermostat you mention can work. The downside is if HA stops, or the remote connection is lost, the control breaks.

I’ve used a combination of both - e.g. a Sonoff relay module, hacked to add a DB18B20 temp probe, Tasmota rules for back-up control, and HA automations for normal use (think of space heating with a complex timer, and a backup frost thermostat).

Shelly devices can get very clever, with local control supporting non-wired sensors like a Zigbee sensor paired to the Shelly NOT HA.

If this helps, :heart: this post!