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Wednesday, March 9, 2011

Phantom Power Usage

Ok...so I'm trying to figure out where a phantom 40w is being consumed.  From Google Powermeter, my always on power is 323w.  This accounts for 7.75 kwh/d...or 20-30% of our average total power usage.  However, because Google PowerMeter averages every 10 minutes, this is skewed.  Looking at my TED data, my min power consumption is around 285W.
 
So the other day I took out the killawatt meter along with TED and started measuring everything...i mean everything.  Htpc, oven, fridge, garage door openers, etc...anything that is plugged in I measured.  For those that I couldn't (dryer, idle hvac and hit water equipment, etc) , I used Ted and the breakers.  My breakdown is below:

Device                              Watts                 Comment
HTPC                               120                (All HTPC equipment. TV+PS3 off)
HTPC Frontend                  30                 (frontend+APC, at plug to wall)
Office Equip                        17                 all office stuff on powerstrip)
HVAC idle                          26                (taken using TED and breakers to off)
Oven/Microw                       7                 (taken using TED at breakers)
Fridge idle                          10                  (using TED)
Garage door                        6                    (Garage door switch lights?)
motion lights (3)                   3                    (photocell?)
Roomba idle                         4                    (not charging)
den tv/remote/switch             5
Cable booster power            7
alarm clocks                         3
Dirt Devil charge                  2
washing machine                  1
Dryer                                   0
Doorbell                              2kVA. Measured using multimeter.  Does not include efficiency!!!
downstairs phone charger     0
TED gateway                       2
TED display charger            0
Onkyo receiver                   0
bedroom TV off                  0
LED flashlight charger          0
toothbrush charger               0
Lamp (w/CFL)                    0

Total                                  245


Avg “always on” wattage:   ~285  (6.84 kWh/day)  - From TED.


Missing wattage:                  40


Cost of missing wattage:        0.082    per day
                                            2.49      per month
                                           29.87    per year

I can account for 245w...but I'm missing 40w!  Where is it being used?!? I even measured the doorbell using my multimeter (2w, btw).  I can't imagine this is line losses.  I realize that it isn't a lot of money...but still, it's the prinicpal of it, right?  Would you leave a 40W light bulb on 24/7?  Yeah...didn't think so.   I'm not in the mood to be giving out a complimentary $30/year to the electric company.

My plan this weekend is to turn off the power to all the breakers except TED.  Then I'll start flipping breakers on, one by one, to account for power usage by room/area.   Since my breaker box isn't labeled, this will allow me to start labeling some of them anyway.   Actually, I'll probably start by turning the breakers off, one by one, to measure the reduction....and then do it again on when I turn everything back on to see if I can replicate the power usage (scientific method, style!)

So...any thoughts out there what this could be?

1 comment:

  1. Thinking about this more along with discussions with a good friend (Nicol), our guess is that the "phantom" power usage is not phantom...instead it's error. Take all those zero power usage. Those really aren't zero, but instead they are less than half a watt because the killawatt and TED meters read in full watts. Well...add up all of those, plug assume there's the same error up above and I can easily make up 13W (26 items listed x 0.5W) just from that list above. So, then if I start factoring in all those other thinks that I didn't put in that list above and I bet I can make up the rest. So this makes me feel a lot better...

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