Quote Originally Posted by Norton View Post
240v, 50w consumes 49.99 watts of power (kw hour is power company unit of charge)

12v, 50w consumes 50.00 watts of power (kw hour is power company unit of charge)

12v will run cooler.

If power consumption is your priority use 220v and save the cost of transformer.

Been a long time since I used ohms law so if wrong, go easy on me.
yep, norton is correct, and so is ohm's law.
watts is watts and that's watt you will pay for, whether it is 12 volt or 220.