Computer Power Usage Question.

[stop!theradio]

Alrighty, I don't know much about amps and actual power usage and stuff like that - so I'm wondering if any of you might be able to answer some questions for me. What is the actual power consumption of a computer with, say, a 250-400w power supply compared to something like a fridge/freezer or a washer/dryer? What is the most power-consuming thing(s) in a household? I'm just curious as I'm being told that our electricity bill is high due to the 2 desktop computers in the house, and I'm really having a hard time believing that's the case. Any input?

 

[obobski]

Alrighty, I don't know much about amps and actual power usage and stuff like that - so I'm wondering if any of you might be able to answer some questions for me. What is the actual power consumption of a computer with, say, a 250-400w power supply compared to something like a fridge/freezer or a washer/dryer? What is the most power-consuming thing(s) in a household? I'm just curious as I'm being told that our electricity bill is high due to the 2 desktop computers in the house, and I'm really having a hard time believing that's the case. Any input?

depends on the draw imposed on those PSUs, and the other appliances in question

if we assume a 400W PSU at 50% load you've got a 200W DC draw, assume its like whatever 75-80% efficient, so around 240W at the wall (give or take), which is around 2A, about on par with a pair of 100W lightbulbs

a dryer will easily use more power, if its electric, as its drawing something like 20-40A on 220V, depending on the model and settings used, which is something in the realm of 4000-8000W of draw

if its a gas dryer, its power usage is going to be far lower, because its burning gas to create heat

in the average household, the majority of power is used on lighting (because most people still haven't gotten the memo on energy saving bulbs), electric clothes dryers, microwaves (~1500-2000W at the wall), and A/C plants (which can easily get into the 20-50A range on their own)

as far as desktop computers running up the powerbill, its very possible, but not if they're using 200W PSUs, if you had a pair of beast gaming boxes with 1kW PSUs drawing 6-7A a piece then yeah, I'd agree with that assessment (I've seen friends' power bills to confirm that such a setup is ridiculous to run loaded 24/7), but the average desktop PC uses less power than most kitchen appliances, and in some cases less power than the average lightbulb

one thing to note:
if you're 14-15 and this is your parents yelling at you that your PCs are driving the bill up, just turn your PCs off when unused, because I'm going to venture a guess they're just using the "the power bill is too high" line to get you outside or doing whatever else they intended

also, if you're not in the US, and live in an area where energy is much more expensive, even the 2A load might be quite a bit to pay for continuously

 

[stop!theradio]

Thank you very much for the explanation. My fiancee and I are living with her parents until we get a good amount saved for the wedding, and they think that a combination of our desktop and their desktop is what's causing our electricity bill to be around $800. They like to act like it's NOT because they feel the need to run the A/C 24/7 during the summer, and ignore the fact that if the price were due to our computers - then it would be $800 in the winter as well, and not just the $90 that it normally is.

Anyways, I was just wondering about realistic computer power usage compared to other household appliances. I was pretty damned certain that their 2003 Dell with 512mb and onboard video wasn't causing the "issue". My setup is in the sig. While it's not as power-friendly as their computer, it's far from being the reason that the bill is so high.

 

[obobski]

Thank you very much for the explanation. My fiancee and I are living with her parents until we get a good amount saved for the wedding, and they think that a combination of our desktop and their desktop is what's causing our electricity bill to be around $800. They like to act like it's NOT because they feel the need to run the A/C 24/7 during the summer, and ignore the fact that if the price were due to our computers - then it would be $800 in the winter as well, and not just the $90 that it normally is.

Anyways, I was just wondering about realistic computer power usage compared to other household appliances. I was pretty damned certain that their 2003 Dell with 512mb and onboard video wasn't causing the "issue". My setup is in the sig. While it's not as power-friendly as their computer, it's far from being the reason that the bill is so high.

I stopped reading at "run the A/C 24/7" -> thats a solid double digit (maybe even triple digit, if its a big enough house) amperage draw, thats thousands to tens of thousands of watts (in other words the meter (which measures in kWh) will actually move in real time in response)

that setup in the sig shouldn't be drawing nearly enough to run the bill up like that

now for some grins, the DOE estimate price per kWh (averaged across the US) is around $0.12/kWh, so if you're paying $800 out, thats something like 6700 kWh, which is around 7 times the national average (oh yeah), no way in hell your sig rig and some 5 year old Dimension P4 is adding that additional ~5800 kWh (nat'l average is in the mid 900's, as of 2007), since that'd require around 190 kWh a day of consumption from the two boxes, which is something like 8000W of power draw (oh hey, thats roughly what a 40A device on 220V, such as an air conditioning unit, will draw )

just realized we could get a more accurate picture if we figured out what your $90/mo is buying, that averages out to like 750 kWh (meaning you're under the national average, good job), so you're using roughly 6000 kWh over normal/winter usage per month, which comes to like 200 kWh a day, or around 8300W, meaning your A/C draws roughly 37.7A on 220VAC while its on

ideas on the power bill:
see if your energy company offers an averaging system, it might drop your bill (if summer is only 2-3 months where you are, it may drop it a lot when you average $800/mo for 2 months against ~$100/mo for 10 months)

but beyond that:
turn that shit off.

on a side note:
this thread made me lol

 

[stop!theradio]

Ha ha, thanks for your help.

 

[Zero82z]

they think that a combination of our desktop and their desktop is what's causing our electricity bill to be around $800. They like to act like it's NOT because they feel the need to run the A/C 24/7 during the summer, and ignore the fact that if the price were due to our computers - then it would be $800 in the winter as well, and not just the $90 that it normally is.

It is impossible for two low-end or mid-range desktop computers to account for a 900% increase in the power bill. Two computers consuming 400W from the wall each would result in a $60 per month increase at a price of $0.10/kWh. Your actual power usage is most likely lower than that, so the true cost is lower than that.

 

[obobski]

Ha ha, thanks for your help.

heh, no problem

got a good laugh out of it as well

honestly I'd look into an averaging scheme, a lot of utilities offer them, and it can save your bill if you have a few months of high usage and the rest of the time things are relatively "calm" (if you paid ~$800/mo for two months in the summer, and $900 for the remaining 10 months of the year, averaged, your bill would be like $200/mo, might be worth a look at least)

 

[vjcsmoke]

Goto this page here and you can calculate your own psu requirements.
Just fill out the components and hit calculate.
http://extreme.outervision.com/psucalculatorlite.jsp

Ok must read more closely. Yeah, like someone said, it's probably the inefficient electricity guzzling AC unit running 24/7. Over the long haul a more efficient heat pump system could save you HUNDREDS of dollars and keep you cool.

 

[MrF]

You can measure how much power each utility, even the fridge or air conditioner, uses with a device like this:
http://www.newegg.com/Product/Product.aspx?Item=N82E16882715001&Tpk=kill-a-watt

 

[ericsan]

Thank you very much for the explanation. My fiancee and I are living with her parents until we get a good amount saved for the wedding, and they think that a combination of our desktop and their desktop is what's causing our electricity bill to be around $800. They like to act like it's NOT because they feel the need to run the A/C 24/7 during the summer, and ignore the fact that if the price were due to our computers - then it would be $800 in the winter as well, and not just the $90 that it normally is.

Home power usage has been a pet project of mine in our house and for my neighbors. We are in Hawaii and our power bill was approaching $0.30 KWH in July. Pretty scary!! My friends in AZ are up to almost $0.08 KWH. So our usage is closely monitored.

Lets say you pay $0.14 a KWH - $800 a month is 190KWH a day. Pretty high.

The biggest culprit in most multi family homes is the DRYER!! Most electric dryers pull 5,000 watts or so. So for a 50min load - thats over 3KWHs. Luckily most newer dryers are only heating half the time or it would be 5KHWs. 2-3 loads a day is 8-9KWHs a day. How may kids are home? How may towels do you dry a day?

So if you are doing twice the # of loads of laundry living with your parents - the electric bill may really jump. My advice? Dry the heavy towels and jeans on the line!! That alone saved us $$$'s

Next is the water heater. If you have electric - then doubling the water heater usage will really make a jump in the bill. A single shower can take up to 2KWHs of power, then add more dish water, etc etc. Our heater pulls 4500 watts. (yes - we need solar - but its very cloudy at my house most of the time). Hot water can be to 20-30KWHs a day.

Third is the AC. You would think that would be first - but if you have electric water and dryer - its third, trust me. Our central AC draws only 2300 watts. And it doesn't matter how may people are in the house - same bill for 2 people or 6. (unless its multi zoned). Our AC in Florida ran about 25KWHs a day and we had a big house 24x7 AC.

Something in the house is taking a huge amount of power. Now the AC unit may not be very efficient Can't be the PCs. Either the water heater is all sludged up, or the AC is low on freon, or there are dozens TV's and lights on 24x7 to hit $800 a month.

Aloha

 

[vtwo]

this is an enlightening thread, a lot of informative responses!