Kill A Watt - standard vs. EZ

I have no personal experience with either of these, but the top of the KAW review on the Gadgeteer refers to the EZ as being the "new and improved" version.

 

I just got one of these for my birthday. I think I have the non-EZ version. It's really easy to use and makes measuring consumption a snap. You can also look at instantaneous draw, which is cool. I've measured a few things thus far (just got it on saturday). I'm really interested to see what the fridge draws but I've yet to pull the bugger out from its recess and plug in the kill-a-watt. It's a cracking little device, you'll have fun with it no doubt.

 

I have the original Kill A Watt and it works great. After seeing the EZ I think I might get one because of the backup battery. The original will lose your data when the power goes off.

 

Get the cheap one. Under $20 if you look around. I have been using the simple one to test everything in the house. It is amazing what kind of phantom loads are out there. (The add up to MORE than my fridge draws in an average day!

Icarus

 

Tony

I don't own the gadget, but I saw no mention of PF Correction or Power Factor Correction. The gadget probably assumes 115 VAC, which is what is stated in the brochure I downloaded. Ok, is that RMS? What happens if you are at 125 VAC RMS?

Is the load an average? How does it respond to inductive loads? Eg, a fridge or freezer has an electric compressor, that is an inductive load. Capacitor start? What does that do to PF?

We use this AEMC at work for power quality and cost measurements:

http://www.aemc.com/products/pdf/2130.74.pdf

Yes, I realize this device is priced far beyond the average homeowner. However, it can do power consumption analysis in VAR, watts, or VA, so it will tell you whether the consumption is capacitive or inductive.

I suppose you are familiar with older power supplies used in offices and commercial/industrial applications? The PF was terrible in them, so much so it was mandated for newer power supplies to offer some sort of PF correction. This is a good primer

http://www.fairchildsemi.com/an/AN/AN-42047.pdf

So if you want to determine how much is costs to run a Prius block heater, this gadget should work. A fridge or freezer, maybe. I suppose I'm being picky

jay

 

In that case, get the AEMC

 

Jay,

The Kill-A-Watt does compute real and apparent power. It will show you W, VA, PF. It won't show inductive vs capacitive (relative phase).

Probably not quite as accurate as the one you describe, but the Kill-A-Watt only costs $20!

Marc

 

I have the standard model. Works fine, the only major drawback from my perspective is that it doesn't hold the reading and it doesn't have a backlight. When you unplug it, the reading's gone. That makes it hard to read if it's in a tight space or at odd angle to your line of vision. Unless the new/improved solves that, I wouldn't pay more for the calculator function. But you can't beat it for $20.

I bought mine to validate my decision to replace my fridge, but found that it has excellent play value in addition to serious uses. My kids thought I was a bit of a Scrooge when I set the blink pattern on the Christmas tree lights to minimize average current draw. But they got it -- they understood that light means energy use. Even showed them that the flat-screen TV uses more power when the screen is light than dark. And they can see that I'm not a nut when I tell them to turn off the power strip after they turn off the electronics.

 

We (my club) own both the Kill-A-Watt and Watts-Up Pro and the Watts-Up Pro seems to be more accurate. It does cost quite a bit more but the simple fact you can link it up to a computer and copy the built-in spreadsheets makes it a better buy in the long run.

 

NewEgg.com has em for about $16

 

I looked at the specs again, and without going beyond the rather vague sell sheet, there is no way to verify that. True enough, for the average consumer there will not be any difference worth writing home about.

That said, I'm wondering if they assume an average 115 vac while calculating cost or totals? There are some loads you can still find in the home, such as older brick or computer power supplies, that could confuse this gadget

 

Went to look at the improved product, and I see what you mean about price. Amazon shows numerous sellers of the old one around $23, but low $40's for the new one. Original Kill-a-watt will not hold the reading, the new one (EZ) has a battery and will hold the reading. That's nice but I wouldn't say $20 worth of nice.

 

The power factor is there. There are 5 buttons (on my model), it shares a button with the watt setting (toggles). Thanks for the links on PF, I need to read up on that - I vaguely recall that being mentioned in a college class, but I haven't done much with electric motors and power transmission since then, so I wasn't sure what that was all about.

However, at least on one occasion the watt button would cycle between all the settings (voltage, current, watts, kWh, hours, etc.) when it's supposed to cycle between the watts and PF. Went back to normal when I unplugged it and plugged it in again.

One thing I found was the new 46" LCD TV (with backlight reduced for better picture in our room) uses noticeably less power than the old 29" CRT. I didn't expect that.

The fridge had some kind of high power draw for several minutes after the compressor finished running (at least once the sounds went away, which I assume comes from the compressor). I'm not sure what that's all about. I could also see there's a definite difference when you open the door while the fridge is working.

I found I didn't need to worry about the cell phone chargers or laptop plugged in while turned off, even the new TV and Blu-Ray player draws almost nothing while off. But the satellite receiver draws essentially the same off as on (which I had suspected from my days working on receivers), so I turn that off at night now. Cable modem/wireless hub also gets turned off at night.

I was disappointed to find out my furnace is wired directly, I couldn't use the Kill-a-watt on that. Same with lights, so I can't verify if CFLs really save as advertised.

I also bought it at newegg.com, had no complaints. Also got my HDMI cables from them ($7 vs. $50 in the big box stores), thanks to the heads-up from PC on the HDTV thread.

 

$16 is even better! I saw them on Amazon for $20ish. I bought mine many years ago at Radio Shack for about $40. (They don't sell them anymore.)