Homeyscript with heating control algoritme (on/off) for Homey home automation device
I used to have a cheap of the shelve on/off thermostat which was awkward to program and had a temperature variance of 3-4 degrees celcius which wasy very uncomfortable. This algoritme gives me a temperature variance of only 0.5 degrees celcius. which is as good as any smart thermostat on the market at only a fraction of the price.
I recommended a shelly 1 device for switching your heating system on or off. It is cheap and works good in my experience.
https://shelly.cloud/shelly1-open-source/
For the temperature measurement use a temperature sensor that is accurate and able to update the temperature at short intervals (about 1 minute). So you might want to get a sensor that is not battery powered. I use a fibaro binary sensor.