Sep
27
2007

Do you turn your computer off at night?


A computer in a cube land: Image courtesy tigerplish via Flickr.
Working in an office cube-land as I do, I often go home for the night and walk by coworkers cubes and see computers or monitors that are left on overnight. Now, I know why this is in a lot of cases – convenience – but I have also heard the explanation that it takes more power to turn on the computer in the morning than it does to power it overnight, so leaving it on is the “greener” thing to do. I’ve wondered if that is true, and so today I did some digging around on the subject.

According to Evan Mills in the Energy Analysis Department of Lawrence Berkeley National Laboratory's Environmental Energy Technologies Division,

The small surge of power created when some devices are turned on is vastly smaller than the energy used by running the device when it is not needed. While it used to be the case that cycling appliances and lighting on and off drastically reduced their useful lifetimes, these problems have been largely overcome through better design.

And, turning your computer and monitor on and off is not bad for it. That may have been the case in the past, but today computers are designed to handle 40,000 power cycles before a failure. That’s 100+ years of turning your computer on and off once a year every day. It’ll be an object in a museum long before turning it on and off has any effect on it.

So, it is better to turn your monitor and computer off at night, but that does not address the primary reason why most folks don’t – convenience. Many find it bothersome to wait for the computer to start up after being turned off. (Oh the crosses computer-users must bear!) Well, there’s an energy efficient way around that as well.

If you are a Mac user you can put your computer to “sleep”, while PC users can tell their computers to “hibernate”. The hibernate feature significantly lowers your computer’s energy consumption overnight while at the same time allows for quick restarts in the morning. Monitors should still be turned completely off - and running a screen-saver does not save any energy – in fact it consumes significantly more power than if the computer is turned off or placed in hibernation.

And remember, like many other appliances such as your Playstation, DVR or TV, even when off your computer still uses some power running to either an AC adaptor, to maintain local-area network connectivity or other things. The only time many of our modern electronic devices consume no power is when they are turned off.

Do you turn your computer off at night? Why or why not?

Relevant articles here and here.

Your Comments, Thoughts, Questions, Ideas

Anonymous's picture
Anonymous says:

good to know these simple things. thanks science :)

posted on Sat, 10/06/2007 - 4:01pm
JARVIS's picture
JARVIS says:

I do not turn my computer off at night only because sometimes I forget. Its not because I dont feel like waiting, its just that I dont think it uses enough electricity while it is on to drastically raise my bills. We're talkin maybe $2.00 extra at most by the end of the month.

posted on Thu, 03/06/2008 - 10:54am
Anonymous's picture
Anonymous says:

Yeah, but just think. $2.00/mth, is $24.00 per year. If you've got that computer for even 5 years, that's $120.00 you just wasted on nothing. I too will sometimes forget to turn it off at night, but try and make it a habit.

posted on Wed, 04/02/2008 - 12:59pm
Joe's picture
Joe says:

And JARVIS, as my family is fond of saying, its not all about you. Saving energy does not just save you money - it saves energy. The less energy used, the better. Small things add up. For example, for the past couple of years I have tried to remember not to accept a bag for my store bought items so long as I could carry them comfortably. Why get a bag for a greeting card at the Hallmark store for example? A bag for a card? I figured that between this and using reusable bags at the grocery store I've "saved" 300+ bags in that two year span. It does not seem like much at the time - but it adds up. And if lots of people are doing it...

posted on Fri, 04/04/2008 - 11:23pm
Anonymous's picture
Anonymous says:

It's not just about the money and bills,
what about global warming and your computers carbon footprint.

posted on Wed, 02/04/2009 - 10:51am
Joe's picture
Joe says:

Very true.

posted on Tue, 02/10/2009 - 5:11pm

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