100 Ways to Reduce Your Impact

Step 58 Kill-A-Watt

Purchase this device called the Kill-A-Watt.

You can use this to find out what appliances are actually worth keeping plugged in. Simply connect these appliances to the Kill A Watt™, and it will assess how efficient they really are. Large LCD display will count consumption by the Killowatt-hour, same as your local utility. You can calculate your electrical expenses by the day, week, month, even an entire year. Also check the quality of your power by monitoring Voltage, Line Frequency, and Power Factor. Now you´ll know if it is time for a new refrigerator or if that old air conditioner is still saving you money. With the amazing Kill A Watt™ you´ll know “Watts” killing you.

Comments

[kucloth]

"Large LCD display will count consumption by the Killowatt-hour" Hopefully they are not suggesting leaving these devices hooked up all the time. What good is monitoring your power if your power monitors are energy hogs as well?!

[belkorin]

Do you realize how little energy a non illuminated LCD uses? Think about how long your kitchen timer lasts on a single AAA battery. Compared to the energy use of anything else in your house, the energy use of a kill-a-watt is negligible.

[kucloth]

Good point, but a small kitchen timer (why use an electric one anyway, the wind up dingers are just fine...) is hardly comparable to a "large LCD display" It also depends on how the LCD is lit... Screens that need a power inverter for the back light draw a lot of power (no not compared to the fridge..) regardless of their on/off state. An LED back lit device would be MUCH more efficient. Regardless, the point is that using energy to constantly monitor your energy in hopes of reducing your energy seems incredibly counter productive. This type of device could be very effective for giving you an idea of your consumption habits, but would be idiotic to leave on all the time...

[FooGlacticon]

I have a Kill A Watt. It uses a reflective screen with no backlight. Really, it uses an incredibly small amount of power to run the microprocessor and screen. If you ask real pretty I could figure out how much power the Kill A Watt uses with a multimeter.

[thetech101]

All of the ones Ive seen are either non illuminated or have a 5-10 second illumination that is activated by a button on the front. The use only a few (2-4) watts per hour. That's 0.002-0.004 kwh or 0.0002-0.0004 cents!

[FooGlacticon]

Watts per hour! You're killing me!

[kucloth]

Ok, then that sounds a little better. But I am curious... you do realize that 0.0002 - 0.0004 cents for 0.002 - 0.004 kWh means that you are paying $0.001 per kWh.... Considering $0.10 is a better estimate, I'm going to assume you meant 0.0002 - 0.0004 dollars, not cents...

[thetech101]

My bad. I meant dollars. Sorry.

[thetech101]

Oh, and the backlight is physically turned on and off on the ones I've seen.

[martian742]

I am OK with multimeter connected in series and set to AC current mode. Then voltage x current = wattage.

[stuuf]

Voltage times current for AC loads is actually something called apparent power (measured in volt-amps), which is how much power the load draws from the line on each cycle. Inductive and capacitive components also return some power (called reactive power) to the source, and the difference between apparent and reactive power is the real power used (measured in watts) The Kill a Watt measures real and apparent power, which is a more accurate measurements of how much power you're paying for. At least I think that's how it works; I haven't read a whole lot about AC power.