Kill A Watt power meter. Cheap and effective
I consider myself to be fairly energy conscious. After moving into a new home, I replaced all of the incandescent light bulbs with compact fluorescent equivalents. I’m not just talking about the ones that are convenient to change: the one outside, the one high above the staircase, and even the small vanity lights were replaced.
Knowing that my lighting needs were addressed as efficiently as possible, I moved on to things like the thermostat and improving the efficiency of the windows. My wife and I have always been very good about ensuring things are not left on while we are not using them. We frequently remind each other to turn off the lights as we move from one part of the house to another. I’ll admit that it felt pretty good to have taken the time to make these energy improvements not only for the good of the environment, but to keep our bills down.
In order to conduct the testing necessary for a recent Icrontic power supply review, I picked up a relatively inexpensive AC power meter from a local hardware store. As soon as I got home with the meter, I was measuring everything from my computer to the toaster oven. I always had a rough idea of how much electricity certain devices used, but it was amazing to get actual measurements. Many high-drain devices like the 1500 watt toaster oven are used for only brief periods during the day. At least that 1500 watts was being put to good use—you don’t turn on the oven unless you are going to use it and you certainly don’t expect it to use any electricity sitting there idle, or do you?
I listened to a radio program recently discussing the impact of “Phantom Load” on the electricity grid. Small amounts of electricity are constantly being consumed by devices that are plugged in but appear to be shut off. These “sleeping” devices constantly draw power from the grid, twenty four hours per day, seven days per week. With more and more high-tech devices becoming commonplace among modern homes, this load continues to increase. Being a geek and PC enthusiast at heart, I suspected more to the electric load in my energy efficient home than just compact fluorescent bulbs. I was really intrigued by the thought of this and decided to conduct some testing of my own.
I’d like to state up front that this is not a terribly scientific test, so I won’t be providing detailed information on most of the products I’m measuring. I intend for the results to be loosely representative of what you can expect with these types of products. Not all electronic devices are created equally, so please take the results with a grain of salt. The only way to be sure of the power draw of your own devices, is to test them yourself. I took a quick walk around the house and made a list of anything I kept plugged in at all times. I was especially interested in devices that displayed the time while turned off, or had LED standby lights lit. Here is what I came up with:
- Wired speaker phone (backlit display)
- Bookshelf CD mini-audio system (displays time and has a backlit display)
- Small kitchen appliances (Blender, Toaster Oven, Kettle)
- Energy efficient night lights
- 2.4GHz cordless phone base station (phone fully charged and docked)
- Tablet PC (fully charged, turned off and plugged in)
- DVD player (turned off, one LED lit)
- 5.1 Channel home theatre receiver (turned off, one LED lit)
- Nintendo Wii (Both off and standby modes tested)
- VCR (Off, displays time with backlit display)
- 27” CRT television (off)
- Home theatre powered subwoofer (standby)
- Two modern desktop PCs (AMD X2 6000+ and AMD X2 4200+)
- 15” CRT computer monitor
- 22” LCD computer monitor
- 5.1 channel computer audio system
- Network multi-function laser printer
- Internet devices: cable modem, VoIP gateway and 802.11b/g wireless broadband router
It is important to note that some of those devices really “do things” while turned off—for example, the Nintendo Wii is constantly obtaining updated data for the channels, such as weather forecast data. Whether or not this is worth a constant draw of electricity is up to the owner.
Other devices on the list are actually never turned off—like the cable modem and broadband router. I decided to include them in a separate graph as they are pretty commonplace and do contribute to 24/7 power consumption. The average high-speed customer will likely have their broadband devices on but sitting idle for at least 16 hours out of every day. These devices do not qualify as “phantom power” devices but I wanted to test them anyhow.
Here are the results of the measurements:
I must admit, I was expecting a watt or two here and there but some of these devices were pretty surprising. The old CRT monitor I have is used perhaps once per week. It sits there idle, plugged in and consumes 12W day in and day out. Also surprising was the two desktop PCs consuming 15 and 16W. I can understand that a PC may consume some power while turned off. I can see the network LEDs flashing and the ‘motherboard power’ indicators lit. Switching off the power supplies does not totally correct this issue either. Even with the PSUs turned off, about 5-6W is wasted. The Nintendo Wii consumes about 11 watts of electricity when in standby mode, but I’d argue that it at least puts some of that electricity to good use—keeping channel data updated via the wireless radio. Thankfully, there is an option in the menu to power down completely—well, sort of. It still consumes about 2W when completely shut down. At least it is much more efficient than other devices I tested.
What about that VCR that I have sitting there? About 10W are continually consumed to display the time—not a good use of electricity in my opinion—especially considering that I have never bothered to set the time correctly. Another 10W goes down the drain continuously thanks to the mini-CD audio system that I have in the kitchen. It is rarely used. It also displays the time and has a dimly illuminated display. Another 10W is accounted for by my powered subwoofer. It sits in the living room in a ‘standby’ mode of sorts—waiting to receive an input signal to power on. Speaking of subwoofers, the computer speaker system I have manages to consume 6W turned off. I imagine this is to allow the system to be powered up by the included infrared remote. My 5.1 channel home theatre receiver uses about 4W while turned off. The power button remains illuminated, and it is also awaiting infrared commands from the remote control.
Moving down the list, my LCD monitor consumes about 3W while turned off and left in standby mode. It uses nowhere near as much as the old CRT, but there is still some unnecessary usage. The 2.4GHz cordless phone base station consumes about 2W of electricity with the phone docked and fully charged and my ‘wired’ speaker phone consumes about 3W thanks to a continuously backlit display.
On a positive note, the DVD player I have as part of my home theatre system didn’t even register on the meter—despite having an LED constantly lit on the power button and awaiting infrared commands. Clearly other devices are not as efficiently designed. The same holds true for my 27” CRT television—no LED, but it awaits infrared commands. It was not really much of a surprise that the small appliances like the kettle and toaster oven are not consuming electricity while turned off. These are truly on/off devices.
As I mentioned earlier, some of the devices are never really turned off—the VoIP gateway and wireless broadband router for example. The same holds true for the alarm clock and night lights. As you can see above, the wireless router consumes about 12W with the cable modem not far behind at 11W. Although these are not really “phantom power” devices, they still account for a continuous load.
Below is a true depiction of how everything is usually left in the house. You’ll notice that I removed the devices that are not really turned off, like the network devices.
Surprisingly it added up to over 100 watts. So what exactly does that number equate to? The compact fluorescent lights I installed throughout my house are 11 watt models. The amount of electricity used by these electronic devices when powered off is the equivalent of me leaving almost ten lights on in the house twenty four hours per day, seven days per week. That is almost every light on the main and top floors—amazing. This hit such a chord in me considering how careful my wife and I are not to leave one light on for a matter of minutes. I wouldn’t be able to sleep at night knowing that I left ten lights on in the house—regardless of whether I could see them or not. Although 107W may not seem like a very large figure, it is continuous—after a while, it will add up.
So “what can be done?” you might ask. Unplugging these devices when they are not in use is the easy answer. Let’s face it though, this is not terribly convenient—especially if the power cables are not easily accessible. One simple alternative is a power bar, power strip or ‘surge suppressor’ as they are sometimes labeled. Almost all power bars/strips have a power switch. Simply shut off the power bar when you are finished with the devices. You’ll get the added benefit of surge suppression as well. Another alternative is a timer. Some digital timers allow very specific schedules and can be used to shut off certain devices while you are asleep or at work. I’d also encourage energy conscious individuals to pick up an AC power meter and run some of their own tests—you can get a relatively inexpensive Kill A Watt
After seeing the results, I’ve done a few things. It really wasn’t practical for me to unplug everything, but I took the middle road. Devices that I rarely use, like the VCR and mini-CD audio systems have been unplugged. I’ve also started flipping the switch on the power bar for my home theater components. I’m hoping that in the future, manufacturers will become more cognizant of phantom load and will start producing more efficient products. Every bit counts.
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