What are the radiator thermostats he mentioned? I have the standard valves on all of my radiators but would be happy to upgrade them.
I haven’t watch the full video but, if he’s mentioned smart thermostats it can mean one of two things. (1) rad thermostats like, Tado, Wiser to name only a couple, control each room you have them fitted individually, similar to a multizone heating set up. Smart rad stats aren’t cheap and not as quite as your normal thermostatic radiator valves. (2) A smart thermostat as in room thermostat (which you have to replace if you opt for smart radiator thermostats)