Measure appliance energy use with a plug-in power meter

Why? Want to find out how much your energy saving efforts are paying off? Plug-in power meters are educational gadgets that can show you the exact amount of electricity your electronics and appliances use. Once you know this information, you can focus your energy saving efforts on those things that use the most energy.
How it works: Connect the meter to an outlet, and then plug a device or appliance into the meter. The meter's screen will display the number of watts the device or appliance is using. Try it out on your TV, stereo, computer and other electronics.

Things to think about:
  • Compare the electric usage of different devices and appliances in your home, and then set priorities. You want to address the biggest energy consumers first.
  • Test out electronics with a meter while they are off or idle. You may be surprised to see how much power they draw even when you're not using them. This process can help you identify devices you should turn off with a power strip or unplug when not in use.

What to look for: Many models are available in the market. These are a couple examples.
  • Kill-a-Watt®: $20-60, measures electronics
  • Watts Up®: $90-190, measures electronics, stores energy data, connects to your computer for usage analysis

Calculate a device's annual cost:
  • Automatically: If you just want a general idea, many meters can estimate this calculation for you. However, only you know exactly how often you use your devices. Your own calculation will probably be most accurate.
  • Kilowatts (kW): How many kW does the device use? Plug it in to your power meter to find the answer. If it displays watts instead, divide that number by 1000 to convert to kW. You'll need to do another, separate calculation if your device consumes different amounts of power while off or on standby.
  • Hours: How many hours do you use the device per day? Remember, if you are calculating standby usage, this includes hours that the device is on, even if you aren't using it.
  • Days: How many days do you use the device per year?
  • Your electric rate: Should be in dollars per kilowatt-hour.
  • Multiply: Multiply kilowatts, hours per day, days, and your electric rate. The result is the total annual operating cost for your device.

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