This has been an interesting experiment. I discovered that my standby (sometimes called “phantom”) loads are about ten percent of my annual electric usage. I thought I was doing pretty good at keeping this under control, but it looks like I will need to buy some more switched outlet strips. The biggest culprit is the laptop computer battery chargers (see table below). I also discovered several other things.
It seems that cellphone chargers don’t waste as much energy as we have been led to believe. I sort of knew this already. After being plugged in for 48 hours in standby e.g. not charging my cellphone, my cellphone charger registered zero energy use. When charging the cellphone it uses about $0.01 worth of electricity per charge. This is one of those small wall cube transformers. When it is not actually charging the cellphone, it is cool to the touch. This is a good way to check those little wall cubes, if it is warm to the touch when it is not doing anything, it is using power and has a standby loss.
Here are a few good ways to figure out if something has a standby loss without using a Kill-A-Watt meter:
- If something has a (wireless) remote control that can turn it on and off, it has a standby loss. This is because some circuitry is actively waiting for the on signal. This includes things like TVs, VCRs, Stereos, DVD players, light dimmers and even ceiling fans.
- If something has a clock or time display, it has a standby loss. Radios, clock radios, microwaves, etc.
- Laptop battery chargers have standby loss
- Cordless tool chargers have standby loss
- If one of those plug in wall cube transformers (like a cellphone charger) is warm when it is not plugged into anything, it has a standby loss.
- Telephone answering machines, cordless phone bases and charging units, internet modems, cable boxes are simply switched on when plugged in. These are not really standby losses so much as actual small loads.
Regarding the cellphone charger; I decided that the Kill-A-Watt meter results were not good enough, so I took it to work and connected it to a very sensitive Fluke Scopemeter to see if I could find out more. Here are the results:
- Samsung Model TAD077JBE cellphone charger, standby mode (not charging) electrical use
- Voltage: 118.6 VAC RMS
- Current: 0.003 Amps
- Power: 0.3558 Watts
To derive the power, I used the current multiplied by the voltage, 118.6 volts x 0.003 amps = 0.3558 watts. Which means that over a one year period it would use 0.3558 watts x 8760 hours = 3116.8 watt/hours. In kWhs… 3116.8 / 1000 = 3.1 kWh. In dollars and cents… 3.1 kWh x $0.168 = $0.52 per year. To give you some idea, an electric clothes dryer uses 4,000 – 5,000 watts per second.
Standby (phantom) loads for typical household appliances:
|
Appliance |
kWh (day) | kWh (year) | pounds CO2(year) | $ Day | $Week | $ Month | $ Year |
| Large TV-Standby | 0.08 | 25.3 | 43.64 | 0.01 | 0.08 | 0.35 | 4.25 |
| Small TV – Standby | 0.06 | 17.5 | 30.19 | 0.00 | 0.05 | 0.25 | 2.94 |
| Weather Radio | 0.08 | 26.3 | 45.37 | 0.01 | 0.08 | 0.36 | 4.41 |
| Telephone answering machine | 0.08 | 26.2 | 45.2 | 0.01 | 0.08 | 0.35 | 4.40 |
| Cordless Telephone | 0.11 | 43.8 | 75.56 | 0.02 | 0.014 | 0.60 | 7.35 |
| Cellphone charger | 0.00 | 3.1 | 5.34 | 0.00 | 0.01 | 0.04 | 0.52 |
| Laptop battery Mac | 0.51 | 175.2 | 302.22 | 0.08 | 0.56 | 2.41 | 29.43 |
| Laptop battery Dell | 0.27 | 245.2 | 422.97 | 0.11 | 0.79 | 3.38 | 41.20 |
| Microwave oven | 0.07 | 26.25 | 45.28 | 0.01 | 0.08 | 0.36 | 4.41 |
| DVD player | 0.07 | 17.2 | 29.67 | 0.00 | 0.05 | 0.24 | 2.94 |
| VCR | 0.13 | 43.9 | 75.72 | 0.02 | 0.14 | 0.60 | 7.37 |
| Ethernet switch/DSL modem | 0.34 | 122.6 | 211.49 | 0.05 | 0.39 | 1.69 | 20.60 |
| Water Filter | 0.00 | ||||||
| Cordless drill battery charger | 0.08 | 61.3 | 105.74 | 0.02 | 0.19 | 0.84 | 10.30 |
| TOTALS | 1.85 | 833.9 | 1438.4 | 0.34 | 7.46 | 11.47 | 140.12 |
Large TV: Philips Magnovox 32 inch
DVD player: Toshiba 5 disk SD-057U
VCR: Mitsubishi HS-U420
Electric rate: $0.168 per kWh
CO2 calculation: 1.725 pounds of CO2 per kWh (US EPA national average 2004)
I intend to do a follow up post on regular appliance use in a week or so.
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Excellent research and incredibly valuable. This shows just how dedicated you are to your readers. You didn’t just bs some numbers you really worked hard at this for our benefit.
Thanks, and now I have to go unplug my 2 Dell laptop chargers.
Thanks for all that information, very thorough.
I guess that like Joe I will be turning off my laptop chargers at the switch from now on, I had no idea how much power they used when not even charging …
Yeah, the laptop batteries surprised me as well. I may put the DSL modem/ethernet switch on a time to turn off at midnight and turn back on at 7:30 am when things usually start happening around here.
Wait until you see the regular appliance use, that one is going to be very interesting when it is done
WOW. This is great. I leave all my laptop chargers plugged in. I will rectify that right away.
Kinda off topic, do you know how to get a mother-in-law to go INTO standby mode? The energy I use to keep from saying something stupid has got to be a lot.
Umm… Your math is definitely wrong.
Umm, where?
Paul,
As I have commented in other places on your blog, we are looking into geothermal heating and air as well as an augmentation to our water heater which supposedly will supply almost 75% of our hot water needs. (This remains to be seen with diva daughter and marathon showers).
What I would like to know is how to figure out how much we are using for the current heat pump and hot water heater. I could look at the overall usage from the power bill but I would like to see the targeted savings if we install this new system.
What method(s) could you suggest to get this information?
Thank you,
Fred
Hey Fred, there are a couple of ways to go about this. The easiest (and least expensive) involves two things; the duty cycle of the heat pump and the current it draws when running.
The duty cycle is just an estimate of how many hours per day the unit runs. Then you will need a clamp on ammeter (perhaps you can borrow one from somebody?). I am assuming the heat pump is 240 volts. When the unit is running, using the clamp on, get a measurement of what each leg is drawing current wise. Mind you, this is the running current, not the start current, which will be considerably higher. I would suspect somewhere in the 8-10 amp range per leg. To derive watts, measure your ac voltage, then it is volts x amps. Example: 123 volts x 8.2 amps = 1008.6 watts. Since it is 240, get the watts for both legs then add them together. For simplicity, lets say 2,000 watts. Then it is a matter of how many hours the unit runs. It likely runs more when it is colder, so you might have to develop some type of curve on a graph.
Another example, when it is 30 degrees outside (daily mean temperature) the unit runs for 5 hours. When it is 40 degrees outside, the unit runs for 3.25 hours. Therefore at 30 degrees, it uses 2,000watts x 5hours = 10 kWh per day. At 40 degrees, it uses 2,000watts x 3.5hours = 7 kWh per day. You may need to get 4-5 data points to get a good idea of use. A heat pump works harder when it is colder because there is less energy in the air to extract. The other thing to be cognizant of it an aux heating coil. This is a straight resistance heater that gets turned on when the heat pump cannot generate enough heat using the refrigeration cycle.
I think you are going to find you are using a lot of electricity to heat your house.
The big cost in a geothermal system is the geo part of it. Often two wells are needed, which can get expensive if they are deep. Good luck, let me know if you need more information