Making Ripples

Making Ripples

Reducing Energy Usage With A Kill A Watt

By Amanda Bancroft

If you already turn off the lights in a room that no one is using, then you’re probably already aware of the value (both monetarily and environmentally) of conserving electricity. But exactly how much energy does it take to watch one movie, or to play three hours of a video game? To determine how many kilowatts our entertainment consumes, my husband and I used a “kill-a-watt” meter to measure each device.

When living off-grid in our earthbag home, we want to watch movies regularly. To do so, we need to purchase enough solar panels to have that opportunity, and we need to know which machines use the least energy.

If you’ve never used a Kill-A-Watt meter, never fear! It’s fairly simple to use. Disclaimer: I am no expert electrician. It measures amps, volts, watts, and more. Ours cost $20. Just plug it into the outlet where you want to use the device you’re measuring.

Then, plug the device into the meter. It will show you the kilowatt hours consumed during the amount of time it’s plugged in, such as three days, and also measures how many watts, amps or volts the device uses in any given moment.

If an appliance consumes 1,000 watts per second over the course of one hour (assuming no fluctuations during that hour) it equals one kilowatt hour (kWh) of energy.

Our current movie setup (DVD player, VHS player and an ancient 13-inch television set) uses 75 watts, so a two hour movie gobbles up 0.15 kWh. But the most efficient tablet we could find online, a Kindle Fire, uses 2.625 watts. For a two hour movie, this would be 0.00525 kWh. For video games, the computer game consumed the most electricity, while the most efficient gaming systems we tested are handhelds.

The best is the DS Lite which uses less than 1 watt per hour of gaming. An hour spent gaming on our computer takes 70 watts. That’s 70 times as much!

If you’re curious about how much energy our refrigerator and other appliances use, check out our blog for those numbers.

Ripples is a blog connecting people to resources on sustainable living while chronicling their off-grid journey and supporting the work of nonprofit organizations. Read more on this topic and others at

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