how do I figure the cost of watts?

jcpainter wrote:

Chris Bryant wrote:
P3 makes a Kill-a-Watt P4455 that does that- you put in your energy cost, it gives you a dollar and cents figure.

Thank you, but this says it calculates by the "week, month, or year".
The one I have already does that.

I'm looking for something that calculates for the time the appliance was actually plugged into it.

All the Kill-A-Watts have a totalizer built in that will give you the total power actually used since you first plugged in the device. If you enter your energy cost, it will also give you the cost of that usage over the time it was plugged in.

As long as you leave the device plugged into the Kill-A-Watt, it will tell you how much energy was consumed. When you press the day/week/month buttons, on models provided with that feature, it divides the total energy used by the time since the device was plugged in and assumes that is the rate at which energy is going to be used in the future.

Then it just multiplies that assumed rate of energy usage by the time in a day/week/month to project what your estimated total energy usage (and the cost of that usage) is likely to be in a day/week/month.