Kill-A-Watt Electricity Usage Monitor ($19.88 / Prime)

killawattI’ve been hearing the “standby power” discussion for a while now: the silly idea that you should unplug all the devices in your home when they’re not in use because they are somehow drawing power and raising your electric bill even when they are off.

I don’t blame people in the slightest for buying into this: a quick Google search finds articles discussing this phenomenon on websites belonging to government research labs, local government websites, and even the U.S. Department of Energy (which claims that Americans spend an additional month’s worth of electricity every year on “vampire power.”)

What these articles all have in common is that they are, like most things that come out of the government, several years behind current technology. Since 2010, and more recently in 2013, new regulations have tightened controls on the acceptable draws of standby power, and advances in technology and manufacturing have made it cheaper in many cases to produce devices without this standby power draw.

A notable exception to this is devices that draw standby power for functional reasons. For example, a coffeemaker might have a small LCD clock and keep track of the time for programming purposes. Likewise, a desktop computer is drawing a small amount of power even when off as it may still be delivering power to USB ports or listening for wake-on-LAN packets.

The Kill a Watt from P3 International is a great way to measure these sources of standby power draw among your own appliances. It is remarkably inexpensive and gets the job done very quickly: simply plug your device into it and press the “watt” button to get a reading of its current usage. (There is also a kWh feature with a clock that lets you measure usage over a longer period of time, which may be useful if you want to monitor aggregate usage or trends. But for a one-time reading of idle wattage, you can measure in seconds.)

I measured a few appliances around my house and here is what I found:

  • Phone chargers, our toaster oven, blender, and big screen Sceptre TVs used no power while turned off.
  • Samsung sound bar: 0.4 W standby power (but ours is always on, which is closer to 2.0 W)
  • XBox 360: 2.0 W standby power. (I honestly expected it to be higher for some reason.)
  • An old Compaq desktop: 3.5 W standby power.
  • A new, custom-built server: 0.5 W standby power (but ours is never off), 33 W at idle, 40 W streaming Neflix.
  • Sceptre 50″ LED TV: 0 W in standby, 101 W when powered on.

Our last electric bill had a kWh rate of $0.0556/kWh, or a blended rate of $0.12/kWh inclusive of all the passthrough fees. (We use Bounce Energy, by the way, which has been pretty awesome and is always throwing us $25-$50 for things like always paying our bills on time, etc. Check them out and see how they compare to your provider. If you sign up using that link, you’ll get a $50 bill credit, and so will we.)

Given that blended $0.12/kWh, we can use the formula W*24/1000 to find kWh usage per day, then multiply by 0.12 to find the cost per day, and another 365 to multiply that out for the year. (You can also use this online calculator to simplify things.)

The end result? The only true standby power draws are the old desktop and the XBox, which represent a combined cost-saving opportunity of $5.78 year. I’m happy to pay that amount each year for the convenience of being able to turn these items on quickly and not have to get under the media cabinet to plug them in.

The remaining devices are things that are on constantly, but it’s still interesting to see their costs. The sound bar runs us $2.10/year to keep on 24/7 so we never have to reach for a second remote. The media server is always on as well, which does get a little more costly at $34.70/year. (That said, it is often doing tasks for me while I am away, downloading files, and available for remote login, so this hardly qualifies as “standby.”) And the TV only draws power while it’s on which, assuming an average of 4 hours per day (for combined computer and TV use by 2 people), costs us $17.70/year.

It’s a fascinating look into the costs incurred by running various electronics and the Kill a Watt can be a great gadget for anyone looking to scale back even just a bit or determine their own power consumption levels. But at the end of the day, the idea of “phantom power” will probably not be enough for most people to warrant any significant action or change in habits.

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