Hi guys, I have not explained well what information I was after.
There is no doubt that electric devices (eg hairdryer, electric heater, kettle etc) are exactly what's on the label and really generate 2000W of heat if the label says so. I have also verified with power meter.
From past experience, and recent tests into a 20m2 room, with 5 thermometers around the room and fan assisted heating, I can say that 2000W is not enough to warm this room from say 13C up to 20C in reasonable time (2 hours). Actually it never reaches 20C (outside temps anything from 0C to 12C) - I switch it off at about 17C-18C.
Central heating, water filled radiators, report their power (in watts) based on the strict condition that [ radiator temp - room temp = 50C, known as "Dt50" ]. To explain this metric, when your radiator is at 70C (average) and your room is at 20C, the difference being 50C, at that precise point the radiator is said to emit 2000W of heat.
Intuitively I know that those radiators produce 2-3 times the heat of the hair dryer or the electric heater, but they are all rated at the same wattage, 2000W.
It follows that the Dt50 power rating for water filled, central heating radiators, cannot be readily compared to our tried and tested electrical power ratings.
Is there a rule of thumb equivalence or conversion, between Dt50 and electrical power ratings?