The ESP8266 measures the temperature and humidity of the room every minute, and in order to know that the heating is on, I added the DS18S20, which measures the water temperature in the boiler.
Now I always know if the heating has been turned on (I see that the temperature of the water in the system is rising) and if necessary I can always turn the heating on / off.
Blynk app :
On one graphic I can see all the necessary parameters and with one click I can turn the heating on or turn it off independently from the thermostat. Each time you update the ESP8266 it reads the RTC data from the Blynk server, performs all the necessary measurements and it updates the time in the app. This allows me to see if the home router is working or not. If it malfunctions and ESP8266 does not have an internet access and thus control, the thermostat will continue to adjust the temperature according to the parameters set.
Thing Speak :
Blynk is a great thing, but there are some limitations when it comes to graphic display, so I also send everything to Thing Speak where I can use Matlab to make additional improvements. This is the plot of water temperature in the boiler for a period of 24 hours. It looks like the heating was turned on couple times.