I was very pleasantly surprised to note that in addition to feel the heat when one is directly in front of the radiator, the room quickly reached the 20 level (where my stove and my heater put much more time).
I bought 2 more for my rooms, where it's well insulated plasterboard, it goes from 14-15 to 20 ° in 1 hour, great for not letting turn the heating in the room the day while I did that very late in the evening ..
Very happy.