Ahh it is 1000 watts
"The electricity to run the block heater probably costs you about ten cents an hour. So 3 hours is thirty cents. But over night of 10 hours is a dollar, and if you leave it plugged in all the time, that's about $2.40 per day or $72 per month. It adds up fast."
Quated from another site, but I thought it was more like 30 cents a hour??
Shrug, its 1000 watts so where ever you are and your electricity is, would be your cost!