Heater

[Stealer Of Souls]

Hey.

My Electric Water Pump (EWP) stuffs up my heater (I knew it could, but hoped it wouldn't) so i'm thinking of doing a complete electric conversion on the heater system (option one).
So. How much heat do I need? 500W? 1000W? 2200W? I figure that since the bathroom heater is 1100/2200W, depending on setting, I could live with about 700W... Of course that's still around 60A @ 12V. Do I really need that much. I'm only really gonna use it for defrosting the windscreen, I don't really need the cabin to be seriously heated (but it would be nice).

I could just put a little electric pump inline with the current heater (option two), but I do like the idea of heating available from the moment I start the car, and even with the car not running I could still have some heat if need be.