“Be kind, for everyone you meet is fighting a hard battle” - Often attributed to Plato but likely from Ian McLaren (pseudonym of Reverend John Watson)

Saturday, July 18, 2009


In May, I attended the Cleantech conference in Houston, TX. While at one of the sessions, a presenter made a passing remark (and held his example up for us to see) about the "Powerkuff." This simple device wraps around the electrical service to my house at the service panel and wirelessly sends a continuous stream of data on power use. Added to information on price, it allows me to see just how much electricity is being used and how much money is being spent.

The device is fairly foolproof, and the output can be read on a small box and sent to a proprietary program through a USB port to a graphical display on the computer, showing power as a function of time. It comes complete and shipped for about $109, and the software to upload usage data to my computer is a free download on the Powerkuff web site. And Chuck Wagner is very helpful and accessible. The software is quite rudimentary, data cannot be stored or output to Excel. But it's still quite interesting.

For example, my "base power" right now (no A/C, no pool pump, electric stove and oven off, etc.) appears to be about 2.1 kilowatts. That's right, the refrigerator plus the various "phantom loads" (Direct TV boxes, DVD players, PS3, televisions, clocks, etc.) are sucking electrical energy and turning it into heat and light and coldness at the rate of 2100 joules/second (2.1 kilowatts). Yikes! In a year, this will amount to over $2,000 just to have food cold and entertainment "ready to go." This needs some rethinking.

With the A/C and pool pump on in the daytime, we're looking at about 7.5 kilowatts. Wow! I've mentioned in a previous post that I estimate my family's use of energy to be equivalent to about 40 kilowatts. This includes vehicles, food, "stuff," electricity at home and work, etc. I had estimated my average continuous use of electrical energy in the house at about 2.8 kilowatts. Now, I'm not so sure. The pool pump goes year around (though not continuously - about six hours per day). Obviously the A/C doesn't but still, I think I may have underestimated.

I live in Anaheim, CA where electricity is provided by Anaheim Public Utilities at relatively reasonable rates and yet I must be spending at least $3,000/year on electricity. It's clearly time to start the same process for my house that I've engaged in with my car. This will certainly be a more difficult undertaking, but the payoff in savings and in CO2 reduction dictates that I undertake it forthwith. I could have gotten the information above by checking the meter and the bill, but like the ScanGauge II I use in my car, the Powerkuff makes it easy and fun to monitor home electrical energy use.

Update: A somewhat frustrating aspect of the Powerkuff is that one must remove the cover of the sensor with a screwdriver to change the three AA batteries. Further, the only way to turn the sensor off is to remove the batteries (or at least a battery). And if you monitor for extended periods, you will be doing a LOT of battery changing. Admittedly, there's a transformer and AC power input so that the unit can be plugged in. But I suspect that, like me, most people don't have an electrical outlet near their service panel.

One could go through a set of batteries every day at a cost of, say, $5. Needless to say, the Powerkuff won't help you save electricity at a rate such as to justify this. I tried using rechargeable batteries (1.2 V NiMH) but they're good for only a few hours, or even less.

The sensor unit needs a switch so that it can easily be turned on when information is being sought and turned off when attention isn't being paid. As I mentioned above, the data can't be stored anyway. Better still would be the ability to turn it off remotely, either from the display unit or the computer. Should I decide that the Powerkuff is something I need to keep, (which is up in the air due to this issue) I'll probably have the power supply wired into the unit from the service panel.


Jeff said...

Thanks.. good info, I have been looking for something like this. I am not sure if the output from my electrical meter is accessible though, will have to look. It might be in a thick pipe/conduit.

King of the Road said...

I'd be very surprised if it didn't work, the strap gives you a lot of play.

steelworx said...

It is too bad that a device piggybacking on a live power line can not get it's power through induction, let's face it, the device is sitting in a great big electric field which it is measuring. Just a thought.

King of the Road said...

I agree completely, I'll pass the suggestion on to Mr. Wagner.