Which is the cheapest heater to use per hour?

[allwornout0]

My house feels like an ice block in the winter, and as I am at home on my own during the day I don't want to put the heating on and heat the whole house when I just need to heat one room.
I have been looking for portable heaters to use in my living room but am confused as to how much they generally cost per hour to use.
I borrowed my parents oil filled radiator and according to my energy monitor it cost 12 p per hour.

Does anybody know which would be the cheapest per hour? Halogen, oil filled radiator etc

Thanks

you're not doing the house any good keeping the whole place so cold. How about setting the TRVs so the less-used rooms are cooler?

if you don't have them they are REALLY worth fitting.

electric heating is the most expensive kind. You are almost certainly better off using the main system if it is fueled from something else.