Designing a home automation system

[Starry_air]

Hi guys. I have a cottage that I'm renting out to tourists. As I don't live in the vicinity, I have to rely on other people, and would like to automate as many things as possible, especially related to heating. The heating system is decentralized, comprising AC units and electric heaters (and an electric water heater I plan to replace with a heat pump boiler). Electricity is expensive, of course, but I don't really have a feasible alternative for a number of reasons. I plan to install a large solar panel array, but even so controlling electricity usage is very important to me.

 

I need temperature sensors, window/door open/close sensors (to switch heating off when doors/windows are open for a few minutes), on/off switches (preferably to install on the power cord itself, so they cannot be uncoupled - I'm using Sonoff's WiFi devices with built-in temperature sensors at the moment, and they work fine, but I think I need to add external temperature sensors to be able to achieve the level of control I need - like setting different temperatures for day/night and so on) and smoke sensors. I would like to keep the price as low as possible (needless to say) and use open-source solutions - because I don't like to rely on proprietary software, and because it usually doesn't offer the capabilities I need. What would be my best option? What devices work well with open source software? I made a simple diagram for myself to visualize where things would go: http://kraa1.sytes.net/nextcloud/index.php/s/p5HWWJRgNakgwxH.

 

Finally, I wonder if it's possible to avoid using my AC's app (Gree) - it's just terrible... though I can live with that, as it's not all that important to fine-tune temperature settings since they are quite efficient. Would the unit get damaged if it were repeatedly turned off and on by a switch instead of self-regulating?

[vetonabdiu]

ohh  Install Home Assistant - Home Assistant (home-assistant.io)
about AC :
If the AC has Wifi and if someone wrote a component (home assistant component) for Gree AC, ur GOLDEN
if not, i think u can use a IR blaster or smth