Each week renowned gadget expert Peter Rojas from gadget Q&A site GDGT.com answers your questions about green technology in our Ask A Tech Geek Series. Read on for this week’s installment and submit your questions below!

How wasteful is it to keep chargers/adapters plugged in when not connected to their corresponding devices?

– submitted by Benjamin Lozovsky

PETER ROJAS:
The short answer is: not very much. At least not usually.

But that’s not the whole story. Read on to find out more.


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When not plugged in most wall chargers for smaller gadgets like digital cameras, cell phones, MP3 players, etc. draw a fraction of the power they use when charging something. Most end up using somewhere between 0.5 to 2 watts when plugged in (but not connected to a device), which isn’t a whole lot in the grand scheme of things. Even if you completely forgot about a charger and left it plugged in all day, every day for a month you’d probably end up adding at most about 10 or 15 cents to your electric bill.

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Far more energy is wasted from simply leaving our gadgets plugged in longer than needed or leaving things like TVs and DVD players plugged in 24/7 even though we only use them an hour or two a day (so-called “standby power”). These are power hogs compared with the trickle of electricity used from leaving a charger or two in a wall socket, and so if I were going to focus on changing something, it’d be that.

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Even so, every little bit helps, and while leaving a wall charger plugged in might not make even a noticeable difference in your home’s total energy consumption, in the aggregate, having billions of these things plugged in when they’re not being used does add up. That’s why more and more electronics companies are introducing chargers that draw very little or even no power when not connected to a gadget — and that automatically shut off when a gadget is fully charged. There are also companies making a host of power strips that automatically switch off bigger electronics like TVs when they are not in use, eliminating vampire power.

If you’re really concerned — or just want to know exactly how much power you’re wasting — buy a power meter like the Kill A Watt or Watts Up Pro. They’ll let you measure exactly how much energy you’re using when these things are plugged in.

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WANT TO ASK A TECH GEEK?
Do you have a green technology question you’d like to ask Peter? Submit it to him by leaving a comment on this post or tweeting it to @Inhabitat and/or @peterrojas with the hashtag #AskATechGeek!