I have been in a new build flat - 2 bedroom now for 8 months and submitted a meter reading, the whole flat is run on electric. I told the energy company i was in a 2 bed flat with me and a child and they quoted £50 per month DD. 8 months on I have a bill for £960 meaning i spend £120 a month on electric.
I can only put this down to these heaters that are installed, we have 5 but use 4. Yes it can heat a room as long as you shut the door and don't intend to go out of it again. Once the door is open - heat has gone!
I am looking around at the moment for something cheaper to run and have found a
De'Longhi Dragon 3 TRD0615T Oil Filled Radiator with Timer, 1.5kW which has many good reviews so I have placed it on my wish list whilst i continue to look around. Problem with the flat is that our kitchen and bathroom do not have any windows so we might be in the middle of a heatwave and the flat is like the inside of a fridge.
I don't even have them on all day, but a total waste of time relying on them for heat on a permanant basis. I could see it being useful in a study for a few hours but thats about it. If you want constant heat, dont move out the door or its gone and make sure you have the money to pay for the bill!