"Christopher - the toaster uses 700W whether it has zero, one or two slices in it. The electrical power dissipates the power in the resistance of the element - there is no feedback to reduce that power whether you had the toaster in a totally insulated box, or whether you had the naked element in free space.Yes, there is a second-order effect whereby the resistance of the element is dependent on the temperature and so affects the power absorbed, but it is a minimal effect.Regards - John"