It's nothing fancy, but I have phone alerts if any windows are open when the heating comes on, and I also use the average temperature inside the house as the input temperature for the thermostat (sensors in several rooms are averaged and published via MQTT to a DIYless thermostat).
My plan going forward is to add ZigBee TRVs to the radiators in each room and automatically close any that are already at or over the target temperature.
FREE MEME CHECK!