# Is it better to leave computer on all day or to turn on and off?

1. May 14, 2007

### moe darklight

Hey, I heard somewhere that leaving the computer on 24/7 is better for the disk than turning it on and off as needed. is this true?

I tend to leave mine on for long periods of time when I'm using bit-torrent and uploading or downloading files. and I never really turn it off, I usually just put it to sleep when I'm not going to be using it.

2. May 14, 2007

### Staff: Mentor

Unless you'd be in the habit of turning it on and off several times a day, you don't gain much by leaving it on all the time. If you had it off half the time but also cut it's lifespan in half, it'd still last the same number of years and would cost half as much to operate.

At residential energy rates, it costs about $30 a month or$360 a year to leave a computer on 24/7.

Also, sleep mode wouldn't help you since the concern (ill-conceived or not) is that in starting-up the computer, the warm-up can damage it. And a computer brought out of sleep mode still starts cold.

We've actually discussed this several times before...

3. May 14, 2007

### trajan22

Well if you leave it on all the time you tend to wear out the all the fans and probably your hd to. Whereas if you turn your computer on and off often Ive heard that it wears out the motherboard, due to the power surge it gets every time you turn it on. ( but I would consider that latter more heresay, I read it on a computer forum once but am not really sure if it is true.)

4. May 15, 2007

### moe darklight

so pretty much, either way it wont affect the longevity and performance of my computer?

5. May 15, 2007

### chroot

Staff Emeritus
I think this is erroneous. If you're paying $0.10 per kWh (which is rather high), a 150 Watt computer would only cost you$10.80 per month.

- Warren

6. May 15, 2007

### tacosareveryyum

Save electricity! Turn off the computer when it is not in use. It not only saves money but is also good for the environment.
However, if you would rather leave it turned on the put it to use! Look up www.hardfolding.com and put that idle cpu to good use curing diseases!

7. May 15, 2007

### Staff: Mentor

$.10 for residential is unusually low, though it does depend on where you live. I typically use$.13 in calculations for residential (and I did here), but looking it up, it is actually $.15 for the first 500 kWh and$.17 for each additional (including 6% sales tax). That's a lot higher than I realized. Here's the rate (pdf page 37):

http://www.exeloncorp.com/NR/rdonly...A998-298A22A4D995/3147/s71_completeUpdate.pdf

150 watts for an idling computer seems pretty low to me, but I haven't put mine on a wattmeter and it of course depends on the computer.

Last edited: May 15, 2007
8. May 15, 2007

### Staff: Mentor

Actually, computers use considerably more energy when their processor is active than when they are idle.

9. May 16, 2007

### FredGarvin

If your computer is a laptop, I suggest putting it to sleep like you are. Laptop HDs do not have the longevity that desktop models have.

If it's a desktop, I think the only thing you really need to worry about s the monitor. If you have an energy star compliant monitor, you should have a setting in your power management to shut the monitor off after a time period of inactivity.

http://computer.howstuffworks.com/question328.htm

Last edited: May 16, 2007
10. May 19, 2007

### rcgldr

Assuming your computer is running Windows, it's going to need a reboot every now and then anyway.