How Kill A Watt Works

Other Energy Monitors

Pricier products will help you track your electric usage with constant feedback.
Pricier products will help you track your electric usage with constant feedback.
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If you're really just looking to find out how much electricity you're wasting by leaving your computer on all day instead of shutting down when you're not using it, a $25 Kill A Watt is probably all you need. You may be looking for some added frills, though.

Here, a sampling of other energy-monitoring devices and what they have to offer:


  • Watts Up? -- Watts Up ($110) is a single-appliance monitor like Kill A Watt EZ, but it's especially fast. It responds to changes in voltage so quickly that you can see the electrical spike when you first turn an appliance on. It records the highs and lows so you can see power surges and poor line quality later on when you check the device. Watts Up? Pro ($210) will also do some additional calculations for you, including your monthly energy savings and how long it would take you to make up the cost of a more energy-efficient appliance.
  • Doc Wattson -- Wattson ($280) is a whole-home system. There's a monitor that you hook into your home's power supply, and a display that you put wherever you'll notice it most. The monitor wirelessly sends your house's electrical data to the display, where you can see all the ups and downs as you turn appliances on and off. In addition to displaying kW/h and total energy cost, the display glows red when you're using a lot of power and blue when you're using a little, making it even more difficult to ignore your energy consumption.
  • Energy Joule -- This is one of the coolest energy monitors out there, but you can only get it if your power comes from Consumer Powerline energy company. It does what any other energy monitor does but with one very special addition: It knows when the cost of electricity goes up and down, because it gets constant feedback from the power company. So you can see when the best time to do your laundry might be. And you don't even have to guess at it, because Energy Joule counts down to lower-cost power. If you need to do a load, but you check the display and find you've only got nine minutes until reduced kW/h rates, you may decide it's worth it to wait.

Even though it's not widely available, Energy Joule is worth knowing about -- if you and a few thousand of your friends call your own power company and request it (or something like it), maybe you'll be able to start counting down to savings, too.

For more information on energy monitors, Kill A Watt and related topics, look over the links below.

Related HowStuffWorks Articles

More Great Links


  • Cut Your Electricity Costs With An Energy Monitor. The Greenest Dollar. March 11, 2009.
  • Energy Monitors. Consumer Reports. March 2009.
  • Kill A Watt. P3 International.
  • Kill A Watt PS. P3 International.
  • Lower Your Monthly Energy Bill and Save Money: Kill A Watt. Smart Home.
  • Monitor and Save Money and Energy: Kill A Watt EZ. SmartHome.