Not really bad arithmetic, but this seems like the appropriate thread for this grumble:
I've noticed a journalistic trend towards the use of kilowatt-hours per year to express power. I mean, it's a potentially useful unit as a step towards calculating the running costs of a thing, but it's not exactly intuitive. If you want to impress us with how power-hungry the thing is, use Watts - most people have a sense of what Watts are. If you want to tell us how expensive it is to run, use the appropriate currency unit. Otherwise you might as well express it in Pirate-Ninjas.
(I'm suspicious this is due to nobody under the age of 40 having used a 1-bar electric fire.)