cost to leave on all the time

Electric aint cheap these days so wondering what the cost is of leaving my laptop all the time.

The AC adapter on my Compaq says 65 watts. And at 15 cents per kWatt hour I'm estimating ~ $7.50 a month [ (65/1000) * $0.15 * 30 days ]

Would you say this accurate?

Now my monitor and hard drives go into sleep mode when I'm not using it so I'm assuming that reduces the cost significantly.


Looking for comments, perspectives etc. Thanks.

 

Yup! I think thats about right! hmm so... its cost aroundthe same to leave a light on as leaving a laptop on...

 

You're close. You've got your cost per unit of electricity, but 65W is not an accurate representation of what your laptop consumes - that's the maximum sustained output the power supply is rated for - not necessarily what you're consuming.

You need a device like the "Kill-a-watt" that can measure power consumed per unit time. Obviously, your laptop will consume more power when running 3D games vs. browsing the web. And it will consume much less power when the display and/or drives go to sleep.

The "Kill-a-watt" can measure your consumption over a 24 hour period (measure on a typical work day). Multiply that by 30 and you've got your monthly estimate. My guess is it'll be significantly less than what you've calculated, assuming your using the ACPI features.

 

I don't even want to know the cost of my desktop with my OCZ 750w PSU.

 

It will be significantly less.

My notebook consumes about 40W idling. I assume yours will be less. With the display and HD in sleep you should probably save another 10 or so...

 

YOUR 750 WATT PSU DOES NOT CONSUME 750 WATTS ALL THE TIME.

 

These are the Kill-A-Watt readings doing various things on my dv9000t (in Watts):

• Heavy disk access: 40
• Idle: 35
• DVD burning: 42
• Off: 1
• Startup: 55
• Processor multimedia test (sandra): 63
• Arithmatic test (sandra): 55
• Multicore Efficiency (sandra): 57

All you really should be looking at is percentage comparisons. I never talk about money on this topic, because the price of energy does not currently reflect the true cost of energy.

Usually when you try to calculate the cost, you wind up realizing that "wow, spending $1500 on a laptop is going to save me $1.25 in electricity!" The comparison is not favorable, and people start to use the context of how long it will take for the electricity savings to somehow pay off their new purchase. It just doesn't work.

All you need to know is that you saved %60 when compared to your desktop. Another context is comparing it with leaving a light-bulb on. Then you realize how bad light-bulbs are.

 

Do you guys leave your lappy's and desk units on all the time? I was wondering if it extended the life of a unit by a significant amount if you shut them down at night or does it even matter. Sorry if this is a stupid question.

 

Most consumer PC's are not meant to be running 24/7, so I'd say it is better to shut it down at night unless you have reason to do otherwise. Or at least suspend/hibernate it.

 

It does not extend or shorten the life of a unit to leave it on or off. I'm still in the process of switching from my desktop to the laptop, but I basically turn the desktop on when I get home from work, and off when I go to bed. I plan to do the same with the laptop.

The power savings alone (percentage, not money), is enough of a reason to turn off the system when you're not using it. Sleep and hibernate are good options too.

 

I would never leave something on all the time just because of electrical storms if nothing else.

 

Whether they are on or off, if a surge wants to go through something, it will.

I used to leave my desktop on since I was folding@home, using it as a file server, and receiving backups. It didn't have a major impact on the electrical bill, but as the summer months arrive, it just makes my room a bit too warm.

 

I'm usually opposed to those sorts of distributed projects, though folding @home isn't SO bad because it actually might have some use someday. Looking for aliens is a total waste of natural resources

 

Uhm, it absolutely does. Probably not to a degree where expected lifetime would beat absolescence but it certainly decreases lifetime.

 

x2 agreed.

 

This is always the rumor floating around, but is there any hard evidence of this? If a hard drive fails, is it because it was left on, or because it was faulty and would have failed anyway? Is the "jolt" of turning something on and off worse than leaving it running all the time? The truth is that you can never know.

One test I use in these situations is "Does doing one thing make an obvious difference over doing the other?" The fact that there is no clear answer tells me that it probably doesn't make a difference. There are many pages debating the issue, which more or less proves my point that there's no clear answer.

I lean towards turning them off to save power.

 

Best way to test would be to test the power on voltage surge, like they did on mythbusters with battery's. I doubt that turn on jolt would do anything,

 

All products are designed with a life expectancy.... meaning they are designed to break after a certain amoutn of time, if they don't break, you won't buy more from them will you?

 

I design electronics for a living. I can assure you most consumer grade electronics have a limited life expectancy. Most obvious example: fans. Expected lifetime for really good ones: 50 000 hours. Sounds like a lot, but that's actually only 5 years or so.

That said, 5 years is still a lot longer then your perceived obsolescence point, but the statement that leaving electronics on won't affect lifetime is false.

Elcos are also notorious for failing when heavily loaded, especially el cheapos.