Lori Bongiorno

Energy vampires: Fact versus fiction

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It's well-known that most electronic devices in our homes are sucking up energy even while they are turned off. But for all the information out there, many questions remain. I got hundreds of reader questions after writing the post What's wasting energy in your home right now. Below are answers to the five most common inquiries:

Which electronic devices waste the most energy when they are turned off but still plugged in? 

Set-top cable boxes and digital video recorders are some of the biggest energy hogs. Unfortunately, there's little consumers can do since television shows can't be taped if boxes are unplugged. It also typically takes a long time to reboot boxes.   

However, some of the other major consumers of standby power are more easily dealt with: computers, multifunction printers, flat-screen TVs, DVDs, VCRs, CD players, power tools, and hand-held vacuums. The Lawrence Berkeley National Laboratory (LBNL) measured standby power for a long list of products.  

While it's true each individual product draws relatively little standby power, the LBNL says that when added together, standby power can amount to 10% of residential energy use.

Why do electronic devices use energy when they are switched off?   

Electronics consume standby power for one of two reasons, says Chris Kielich of the Department of Energy. They either have an adapter that will continue to draw electricity, or they have devices (such as clocks and touchpads) that draw power. Anything with a remote control will also draw standby power, she says, since the device needs to be able to detect the remote when it's pushed.

Does everything suck energy when it's plugged in and turned off?

No. If your coffeemaker or toaster doesn't have a clock, then it's probably not using standby power, says Kielich. Chances are your hair dryer and lamps (although they may have a power adapter for the dimmer) are not drawing standby power either, she says. Devices with a switch that physically breaks the circuit don't consume standby power.

Will switching things on and off shorten their life?

Probably not, says Kielich. You'd have to turn devices on and off thousands of times to shorten their lives. The real downside, she says, to unplugging electronics is that clocks and remotes will not work, and you do have to reset everything.

Can you ruin batteries by unplugging battery chargers and causing batteries to completely discharge?

It could be a possibility, says Kielich. Her advice: Don't let batteries get completely drained. But you don't need to have things like hand-held power vacuums and drills plugged into the charger when it's 100% charged, or even 50% charged.

Power Strip FAQs

Plugging electronics into a power strip and turning it off when you're not using it is a widely prescribed solution for curbing vampire power. Here are answers to common questions: 

  • Power strips draw energy when they are turned on, but not when they are switched off.
  • Any decent power strip should have surge protection, according to Kielich. Flicking your power strip on and off will not create a power surge capable of damaging electronic devices. In fact, it will protect devices from other surges. 
  • Several readers were worried about the possibility of fires caused by plugging too many things in at once. If you plug in the allowed number of devices, then power strips are safe, says Kielich. Just don't plug your power strip into another power strip, or you run the risk of creating an overload. 

Environmental journalist Lori Bongiorno shares green-living tips and product reviews with Yahoo! Green's users. Send Lori a question or suggestion for potential use in a future column. Her book, Green Greener Greenest: A Practical Guide to Making Eco-smart Choices a Part of Your Life is available on Yahoo! Shopping and Amazon.com.

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comments from our community

Showing 16 - 30 of 645 comments

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  • Posted by *Dragondrew Sat Mar 7, 2009 8:38am PST
    Interestingly, in Europe nearly every outlet has its own power switch so you can leave devices plugged in while still cutting all power to that device. Maybe we should think about this?
    Report Abuse
  • Posted by smash Sat Mar 7, 2009 8:40am PST
    devices like televisions have to be kept plugged in because the pixels need to stay at a certain temperature, if you leave it unplugged they will warm up faster when turned on and leave open the possibility for damaged pixels, which cannot be individually replaced... you'd have to get a whole new screen.
    Report Abuse
  • Posted by dqueenscott Sat Mar 7, 2009 8:41am PST
    Well,I wanted to know about phone chargers. Do they still use energy even though the phone isnt plugged to it?
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  • Posted by Frank P Sat Mar 7, 2009 8:41am PST
    To expand on what Dee said, NiCd batteries will get a "memory" if you recharge before they are completely drained, and the amount of time between charges will become progressively shorter. With cell phones, for example, when it shuts off due to low battery, wait a few minutes and turn it back on. Do this a couple of times until it won't turn on at all, then it's ready to recharge. My cell's still happily using its original battery from 2 years ago!
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  • Posted by Jeffrey C Sat Mar 7, 2009 8:41am PST
    Tested that actual draw of devices when off and found nearly everything stated as drawing power in standby was false. The real waste is people leaving things on when not in use, such as people that never turn computers off so they sit doing nothing while they sit idle. Same with TVs. In fact I found only 1 device total that had a high draw when in "off" mode, and that was an electrostatic aircleaner. Get off the "Unplug devices to save energy" kick and give people actual ways to save energy.
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  • Posted by Stinky Sat Mar 7, 2009 8:43am PST
    reply to loomis's response - That is so true going to starbucks is a big waste of money as well as fast food (yuck) , but 10% is 10% , and im curious to see if it will save 10% , I think personally it would save about 3-5% and the time unplugging and plugging in every day and night could cause an unfortunate accident with chords pulling expensive items off shelves costing you a fortune when your tryin to save $5.00 a month , not to mention theres already enough stuff we have to worry about every day and instead they are recommending adding more frustration to our lives by trying to turn on the tv with the remote forgetting we unplugged the tv , cable box , and digital video recorder , whats the purpose of a remote controll now , might as well get rid of it a turn tv on with button .... no way im not trying this , i think the way to save money (the best way) Is if you make 10 dollars spend 7 and save three .
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  • Posted by Ken Sat Mar 7, 2009 8:43am PST
    Well GEE WHIZ Mr Professor, Since we are all such power hogs how about telling the people the truth about how much energy is really wasted? A computer that is running but the monitor turned off only uses $3/month of power, turning it on and off only saves you about $.75/month(less energy than your coffee maker uses for one pot of coffee). And YES continually turning a computer or any other electronic device is extremely hard on them (hard drives, fans, Memory cards and the like).
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  • Posted by X Sat Mar 7, 2009 8:43am PST
    Lousy article! Lori is wasting energy with this unnecessary information! This so old info!!!
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  • Posted by jambs04 Sat Mar 7, 2009 8:45am PST
    wow I never knew this was really an issue with how much electricity was consumed when the machine's clock is turned on. etc.
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  • Posted by Dr.JonathanD Sat Mar 7, 2009 8:46am PST
    This article contained no data, just opinions... not even a representative chart, or graphs, or comparisons... it was very! poorly written... and yet, to read people's comments, it appears they are imagining these quantities as included?? Goes to show how people overlay their mental images on top of video presentations, to see... what they think!... is happening! wow...
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  • Posted by International A Sat Mar 7, 2009 8:47am PST
    "standby power can amount to 10% of residential energy use." While I'm all for energy conservation, in all honesty, I am not that bothered about saving an extra 10% ($10-$15 a month in my case) on my electric bill. I'd rather have the convenience of being able to use my electronic products quickly and easily.
    Report Abuse
  • Posted by Angel M Sat Mar 7, 2009 8:47am PST
    Seriously, how much money would I be saving per month if I unplugged half of my appliances and electronics? A couple of bucks? Forget it; not worth the inconvenience. Although I do understand if being "green" were a factor, we should probably still turn off or unplug items that don't need to be reset every time they're turned on.
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  • Posted by Rosa B Sat Mar 7, 2009 8:47am PST
    It is wise to unplug any electronic devices that use electricity overnight!
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  • Posted by Jack B Sat Mar 7, 2009 8:47am PST
    I have always wondered why dont instead of us having to buy power strips they just make them that install into the wall like a regular wall plug? you could put a switch on it and it would save having a big messy power strip...
    Report Abuse
  • Posted by DeloresH Sat Mar 7, 2009 8:48am PST
    I do not agree with all of the artical but Ido keep lights turned off when not in use, forget about the rest.
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