Just bought a Kill-A-Watt electricity consumption meter
 

Just bought a Kill-a-watt for $19.00 including shipping. Couldn't resist.

If you want one try here. Good till 01/13/08

These things rock. I have the Australian version, which I patiently waited for something like 2 years to finally get here. I've since conducted a thorough energy audit of the whole house. I was surprised that some things don't use as much energy as you think. For example, my CRT only used 60W, and it's 19 inch. Of course, an LCD can use half that, easily.

It pays to measure. If only it weren't so difficult to measure drag coefficient.

For real fun with the Killawatt, make sure to measure electronics when they are turned "off".

I have heard that up to %75 percent of all the electricity consumer electronics use is when they are "off"

A VCR, Sattelite reciever, cable TV box all use the same amount of power wether they are on or off.

If it has a remote control, clock, or blinking light, unplug it when not in use.

Absolutely. I think also that the killawatt may not register below about 5W. So if a device uses 4W, it will read 0W. Can Americans confirm?

The way to test this is to plug a powerstrip into the killawatt with a resistive load such as a desk lamp and the device you test into that powerstrip. Measure the difference between your device on and off, with the desk lamp running.

This was the motivation to buy a power strip with individual power switches. Stuff that uses no power when switched off goes on my old power strip, anything that uses power when switched off gets switched off with the switched power strip.

I have noticed the Killawatt seems to be inaccurate at low wattage.

Does anyone know of another product that would be good for measuring low current AC? Something inexpensive, or better yet, a DIY project for how to make one?

Well, seeing as most people use the Kill-a-Watt about once, which is when they audit their house and write down figures for on and turned off, it's easy to just use the Kill-a-Watt.

The trick (not sure if I made it clear) is to measure what you want to measure in parallel with another, bigger, purely resistive load. The difference (with the resistive load on, and the smaller device in question on/off) will be the power draw of the smaller device. Yes, I know that taking power factor into consideration, it won't be exactly correct but it will be close enough.

Mine measures down to 2W IIRC. I don't think I've measured any 1W devices, and the 2-3W was an old microwave.

I got pretty close to accurate readings at 2W testing a strand of LED lights confirmed with multimeter... I haven't really verified things less than that...

I've been doing long term power usage measurements with my kill-a-watt

things like my cell phone charger, laptop charger, etc. The wattage reads as zero (occasionally hitting 1) - but given enough time, it will show up in the kWh reading...

My laptop charger, for example, consumes ~.15kWh per week... I had a spare power brick on the kill-a-watt for three weeks.... Which almost makes me sad because that's less than 8kWh per year if the charger was on stand by the while time... That costs me about 75 cents, a year... It's not like I can go to people with a huge claim of how much they'll save - I find more than 75 cent/year on the street :p

My cell phone charger is almost half that consumption...

Anyone have two kill-o-watts so they can find out how much a kill-o-watt uses? ;)

I have the WattsUp Pro that graphs and found it invaluable for doing run time optimization with a new boiler installed last winter. You could tell when it was idle (14 watts for the controller), when the pump was active (70 watts more), and when it was ignited, the approximate fan speeds all by fixed time intervals (20 to 50 watts more depending on modulation).

I was tempted to get a newer one that had more data storage (as it uses up each time interval range, it basically just uses every other data point and then records on the newly liberated second half so it can go on and on and on with wider and wider data acquisition intervals, although data was quite good over 24 hour periods) to smoothen out graphing and make it more precise for longer runs. I held off... Then I was tempted by it being USB instead of serial as those ports slowly disappear. The latest is web-server functionality so you can monitor it online. I think that last feature might be the real wallet-spreader. It's coming in February, so I'll have to remind SWMBO I have one of those gift-receiving occasions that month! ;)

https://www.doubleed.com/secure/products.php

I'm pretty sure the kill-a-watt monitors lower than 5 watts, but I don't remember getting the impression it was overly accurate.

I'm pretty sure they do... The accuracy drops but who needs even 10% accuracy to measure a 2 watt plug load.

Maybe it has something to do with the voltage difference. Either that, or it's just a different unit. It does have 3 buttons as opposed to more on the kill-a-watt. (up, set and func).

The story I heard from my Australian supplier was that they had such demand for the things in the US that they didn't have the time to make any for 240V!

I've read about this meter at literally tens of places. Ever since I first saw it at Thinkgeek I was curious, how well does it measure power usage on inductive loads?

I just bought one today.

I saw fit to warn the wife that I'll be an even bigger "power nazi" once I get it. :D

The Kill-A-Watt is pretty accurate in my experience. My Wii uses 2 watts in standby (with wiiconnect off). I always keep it unplugged. Most things in my house are on their own power strip, with individual switches to turn each device off as I see fit.

I have a main switch that gives power to the power strip, and the power strip is then divided by device. Very nice stuff, but I am not sure that you can find anything like this outside of Japan. Over here they are common everyday items though...

So to answer newtonsfirstlaw's question, the Kill-A-Watt does display amounts between 0-5, in whole numbers.

I have had some problem with inaccuracy, but only after having it plugged in for a while and turning the device it's measuring on and off.

:eek: Damn, I got my Kill-A-Watt yesterday and soon discovered that my TV uses 25 watts when it's turned off!! When I turned it on the real carnage began. 162 watts, I guess that's the price I pay for a 44" projection screen :o

I already convinced the wife to sell the beast when we move, LCD here we come!

Just wait until you try all the other things around the house and see how much they use when "off".

My biggest suprise was that my GAS oven uses about 300 watts of electricity while on!

Makes me want to bake pizza on top of my wood stove....

AndrewJ: There is a lot of hype behind LCDs. I will warn you though, that they are NOT as efficient as you would be led to believe. I personally have noticed a trend that LCDs use about 25% less than tube-based t.v.s. That really isn't a make or break in my book. The pollutants released during the manufacturing of the LCD far outweigh any savings you would get in electricity. I say stick with your unit that you currently own, and trade up when it dies.

Has anyone checked their refrigerators? I hooked up the kill-o-watt to mine and ended up with about a 17kwh draw per week. This was back in the summer though, so it may have dropped since then. I think I will actually go test it right now!

I ran my fridge through the Killawatt for about a month a while back.

I don't remember the exact KWH, but it was about 1/6 of my total electric bill.

My Fridge is a full sized, LG, which was one of the most effecient ones for its size.

I still plan on getting a Sunfrost for my next fridge.

UPS actually use a surprising amount of power. During normal operation. Can you get a sunfrost without the UPS? Up north the power only goes out in the winter ice storms generally and then we can just move the food outside :) Just a few things like mayonnaise freeze and shouldn't.

Wow this device is pretty interesting. I wonder how much our 59 inch rear projection, which stays on from 3 to 10 most of the time, uses.

No, the UPS on their fridges are an extra option that you can get, their standard fridge is just super efficent, pretty simple, and well built by real people! I've talked to the owner a number of times and he told me they used to offer an option of a heat pipe for cooling in cold climets, but that people didn't understand it so no one wanted to pay extra for it.
We got our sunfrost in 1987, and it's still in use, and as effecent or more so then alot of what you can get today.

The nice thing about the plug in meters is that you can leave something like your TV or cell phone charger pluged in to it for a few days or a week, and then look at the total hours it was monitering, and the total power used, my cell charger draws less then a watt, but it's hard to tell over a short chunk of time.

True Power
 

The newer kill-a-watt will display power factor. However it really doesn't matter. Your Power Factor should be 1 or very very close to 1. What most people are looking at in there homes (in the USA) is 120/240vac single phase.

When calculating Power there two basic ways (1) True Power (2) Apparent Power.

The Kill-A-Watt P4400 can display either one.

This is pretty interesting if you want to track the whole home. You can also track individual circuits (like heating or A/C) and see what the cost and run times are.

http://www.theenergydetective.com/what/overview.html

http://www.theenergydetective.com/im...1001-.5inL.jpg

We have a Vestfrost refrigerator. It uses about 1.1 kWh a day (averaged over a week or relatively normal temps, at least for here (70f during the day). I measured a lot of things with the Kill-a-Watt, but it now resides on the plug for the Citicar. It uses about 1 kWh for four miles, or about 2.5 kWh a day for my 10 mile 'commute' (5 each way). Even with the electric car, our average daily use is about 6 kWh a day.

It was interesting to note the difference between a normal string of xmas lights compared to LED ones this year. The regular bulbs used about 60 watts, but the LED ones used about 2 (two). Our electric bill this December went down significantly...

Who -

This is pretty cool. I like it more than the other "whole house" one whose name escapes me because it actually taps into the voltage instead of "watching" the power thingy spin in the fusebox.

The 400 Amp one might be in our future because we want to install an electric kiln for a home pottery business. With a TED, we would be in a position to exacti-mate our kiln's energy costs.

CarloSW2

definitely don't believe the hype with LCD TV's. I purchased a 37" DYNEX from Best Buy and read the power usage label 220W. Whereas my 18 yo Sony Trinitron 27" tube uses 160W. That TED looks mighty tempting, I'm curious of what my electric range, AC, hottub, and 90% efficient gas furnace use. Those things don't use a plug.

Also the best way to reduce power is light source conversion. I haven't done much yet but I can't stand the fluorescent bulbs so LED's are the next option and its looking like the market is pretty good nowadays.

OBTW, The Dynex was returned, LCD TV's are crap (yes I've spent hours staring at them in the stores). Holding out for laser...

How much does it use when on ? Does the unit have an automatic 'sleep' mode ?

( I'm thinking of all the hundreds of millions of kids that just walk away from a game to go play and leave the things running.
)

I tested my Toshiba m200 tablet PC ( tiny 12 " screen )
In maximum power mode it consumes between 36 and 42 watts ( 42 watts when doing graphic intensive work in my 3D program. )
When on the intenet, I set the power mode to 'normal' or 'low power' mode, which consumes 24/27 watts in normal mode, and 20/22 watts on low power mode.
By itself, the screen comsumes just 8 watts of power.

By comparison, a 20 " iMac consumes 200 watts.
A Power Mac PC ( tower ) can consume over 900 watts even before the monitor is plugged in.

A stand alone 20" LCD monitor typically consumes around 65 -85 W.
If I doubled the area of my laptop screen ( to 24 " ) I would consume just 16 Watts - and this is a very high resolution screen.
How can it be that laptop screens are so much more efficient, yet produce the same results as regular monitors ?

Old Thread, new Deal
$14 shipped from New Egg
Kill A Watt Electricity Load Meter and Monitor - Slickdeals.net

kill-a-watt
 

I have a different meter that does the same monitoring with data logging that can be downloaded to a computer. It helped me to make the decision to change refrigerators after I saw how much energy my old one used in a week.

old thread
 

posting it up

Cd! Wait a minute! You can't double a 12" diameter screen to get a 24" one... you have to quadruple it!

Anyway, I use my 24" LCD around minimum brightness so and this way it consumes much less power (was ~55W when I last checked), generates less heat, doesn't burn my eyes and its "black" is a darker shade of grey :D

(Bad that I can't turn it truly off with the computer and amplifiers because it instantly forgets its color settings. Since day one, it's a bug...)

Check your local library, not sure if it's a widespread practice but ours is offering Kill-A-Watt lending. I may just have to give it a shot this weekend...