# Reply by Bill1974

Posted on Measuring power usage from a tool

 Bill1974132 posts in 3467 days #1 posted 11-16-2015 08:28 PM Since you are looking at the power consumed by an electric heater it’s pretty simple. I am assuming there is only one heating element and it’s on or off. If there is more than one heating element you will need to do a little more math and need one more piece of equipment. I am sure you could contact the mfg of the oven and get the wattage of each heating element. Now you just need to measure the amount of time it is on. There are plenty of cheap timers that you could wire up to the record the on time of the heating element coils. Then its just multiply the wattage by the time in how and divide by 1000 to get he kW-Hr. The looking at you bill you can see what the rate is for the power and the rate for the power delivery and find the true cost. The are meters that you could use to measure the power but they are expensive. Looking at your electric meter is the other option if you can turn off all the power using devices. Measuring the power consumed on devices with motors is more difficult than the voltage x amperage. The power factor of the motor comes into play and can significantly change your power consumption. Depending on the type of motor and load the power factor can swinge from .50 or lower to as high as .99. The electric meter is the most accurate way to see how much power something is using but a challenge to use it to measure one device.

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