Kill A Watt Calculator
This calculator is for the Kill A Watt electricity usage monitor. It’s an excellent tool to measure your electricity usage, but to get the data it gives you into dollar terms, you must perform your own calculations. This calculator will automatically do that for you and give you the device’s cost per hour, day, month, year and 50 years. To calculate a device’s energy use, please input the fields below. For a tutorial and definitions of the terms please read below the calculator.
Kill A Watt Calculator Tutorial
First, you will want to plug your Kill A Watt into an outlet and then plug a device into the Kill A Watt, such as this fan below:
You’re going to want to run the device for at least a few hours. The larger sample size you get in hours, the more accurate your data will be when you run the calculator. Under the screen, on the right side of the device, is the kWh/hour button which is purple and highlighted by the red arrow:
By pressing this button, you can toggle between the time and kWh the device has used. Above, the time is listed as 8 hours and 13 minutes. You would fill that information into the calculator above. Now toggle the button to display the kWh, such as below:
Now input the kWh used into the calculator above. For your local kWh rate, you can look it up in your utility bill or find a general estimate by clicking the link next to the input box. This is the Energy Information Administration’s average price per state. For the average hours per day the device runs, you’ll need to give your best estimate to how often you use a device. For something like a refridgerator, this will be 24 hours. For something like a television, it might be just 3 or 4 hours. Click Calculate Device’s Cost, and voila!
You now know how much your device costs over five different time periods: per hour, per day, per month, per year, and per 50 years. As well, the calculator will tell you the monthly kWh that device uses. This is helpful when comparing the device to your monthly utility bill.
Kill A Watt Calculator Formula
The calculator first divides the kWh used by the time ran. This gives us the kWh per one hour of use. Then:
kWh per hour X local kWh rate X average hours per day ran X length of time = cost of device
Example: The fan above generated 0.22 kWh over 8 hours and 13 minutes. This is 0.026775 kWh per hour.
0.026775 kWh per hour X 0.13 cents per kWh in Santa Barbara X 12 hours run per day X 8766 hours (aka 365.25 days to account for leap years) = $22.28 to run the fan per year.
NOTE: A month is considered 30.4166667 days (this is 365/12). A year is considered 365.25 days to appropriately account for leap years.
If you like the calculator, please share! If you haven’t bought a device yet, get one on Amazon for cheap.