The full power consumption of Formula Ready is 600 watts. If you boil twice a day, that adds up to 3-5 kWh per month. That would cost $0.39- $0.65 at an electricity rate of $0.13/kWh (this is the average electricity rate in the U.S.). For the keep warm function, the power consumption varies depends on the environment temperature, but it would take much less power than the boil function.