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What is a Kilowatt Hour
Saving money on your electric bill starts with understanding what a kilowatt hour is.
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What is a Kilowatt Hour

The power company charges you for power in kilowatt hours, abbreviated kWh. This guide explains what a kilowatt hour is.

We all know that c are rated in watts, such as a 60 watt light bulb or a 100 watt light bulb. How much you pay for using a light bulb on depends on how long you leave it on for and the wattage rating of the light bulb.

Most power calculation is based on hours. If you turned a 100 Watt light bulb on for 1 hour, then you have used 100 Watt hours. Likewise if you turn the same light bulb on for 2 hours, then you have used 200 Watt hours. Notice that we simply multiply the watts of the light bulb by the number of hours it is left on.

Watt Hours = Watts Used * Hours Used

Item used
Time used for
Watt hours Used
100 watt light bulb 1 hour
100
100 watt light bulb 5 hours
500
100 watt light bulb 24 hours
2,400
100 watt light bulb 24 hours a day for 30 days
72,000

The values in the last column get big fast when you start talking about how much power is used in a month. That is why most power use is measured in kilowatt hours. This simply means "1,000's of Watt hours". Using kilowatt hours, the above table becomes this.

kilowatt Hours Used = (Watts Used * Hours Used) / 1000

Item used
Time used for
kilowatt hours Used
100 watt light bulb 1 hour
0.1
100 watt light bulb 5 hours
0.5
100 watt light bulb 24 hours
2.4
100 watt light bulb 24 hours a day for 30 days
72

This last equation is the one that you should remember when doing kilowatt hour calculations.

kilowatt Hours = (Watts Used * Hours Used) / 1000

If you want to know how much you pay for a kilowatt hour, then you should check our our guides to help you Determine How Much You Pay For Electricity.


Lets do some examples.

Example 1: If you used a 1000 watt curling iron for 1 hour, how many kilowatt hours have you used?

kilowatt Hours = (1000 watts * 1 hour) / 1000 = 1 kWh

Example 2: If you used a 10,000 watt oven for 3 hours, how many kilowatt hours have you used?

kilowatt Hours = (10,000 watts * 3 hours) / 1000 = 30 kWh

 

We also have a guide to help you learn to Read You Power Meter to Determine Power Usage.

What Is A Kilowatt Hour
Jason Bauer

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Jason Bauer is an owner and programmer for Portforward.com. He's allergic to twitter and facebook, but you can find more of his articles in the Guides section.
 
Tuesday, 25-Apr-2017 15:10:04 PDT