# Electronics energy consumption 101

I like to understand my daily electronics consumption.  I understand an average desktop computer has a power usage of between 80 and 250 watts hour of "active" use, depending on graphics cards and additional peripherals.    A laptop is 50 to 100 W/hour.  In stand-by mode the power consumption of both a desktop and a laptop falls to about a third.   The cost to the University to operate a typical computer and monitor workstation (130 watts @ 11c kW/h) for 24 hours per day, 7 days per week, 365 days per year, is \$129.73. It appears from electric bill I am 10 kW/h.  My energy use to date start from 2/22 is 207.31 kWh.   I use my laptop and dual monitors pretty frequently for 7 hours a day / 5 days a week.  Can someone explain the math here?

LVL 1
###### Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Retired ITCommented:
watts in use   X   cost/KWH   X    hours per day    X    days per week    X   52 weeks    /    1000
0
Commented:
"Can someone explain the math here?"     It depends on what you want the math to do.

You already have your daily use from the graph.  Your daily cost if the price per kwh times the use. (Take the university cost of 11 cents, or look at your bill).
-
You want the energy cost of your computer equipment?
Measure the usage with a watt meter or estimate from your info which your have.
-
Usage for laptop say 50 Wh    a monitor say 30 Wh     (130 for computer _ monitor minus 100 for the computer)   you have 2
therefore 130 Whr    for 7 hours = 900 W/r
-
Now you have to decide do you put them into standby or not?  I say no, (turn them off) so you  use about 1 kW/day for computing equip.
Obviously an estimate but a good guess.
What more do you want?  cost per day, cost per week, cost per month? Want to fine tune the estimates? If so, just what do you want?
0
Author Commented:
I get that 207kwh total consumption/13 days =  15.92 kwh each day.  So each day I am consuming like 10 to 15 kwh?

A laptop is 50 to 100 W/hour

I am using that a fair (6 to 8 hours) amount during the work day.    How am I getting to that 10 to 15 kwh mark?   I am a pretty poor mathematician.  So really break it down in details please.  thx!
0
Retired ITCommented:
do you also use lights?  Hot water? Furnace / air?  Refrigerator (big watts)? Washer? Dryer?  Stove?

Do you have a router?  Cable modem? TV(s)?  Wired phones?  Do you charge devices (iPad, phones, razor, toothbrush)?  Do you leave chargers plugged in?  Do have a printer? Scanner?  Sound system?   Home security?  Sprinkler system?  Coffee pot?  Toaster?  Vacuum cleaner?

All this stuff adds up KWH.
0
Author Commented:
Yes.  I'm trying to perform the math for just one item.  Then I can do the math for the rest.  So again,. A laptop is 50 to 100 W/hour.   Is that separate than KWH?

I am using that a fair (6 to 8 hours) amount during the work day.    How am I getting to that 10 to 15 kwh mark?   Please assist in the equation.
0
Retired ITCommented:
1 KWH  is 1000W consumed for an hour.
0
Commented:
let laptop use 100 watts for 1 hour   that is 100 watt hours  (watts times time)      that is 0.1 kw hour     (1 kw = 0.001 watt)
next
0.1 kw hour for 10 hours = 1 kw hour
-
-
(the 10 kwh figure includes monitor energy)
0

Experts Exchange Solution brought to you by

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Author Commented:
Thank you, it all clicks now.  Sorry, you needed to spoon feed me.
0
Commented:
"Sorry, you needed to spoon feed me."
-
Spoon feeding is better than starving
0
Author Commented:
Is the data I input on this link based on daily, monthly, or yearly usage?

https://www.epa.gov/energy/greenhouse-gas-equivalencies-calculator
0
Commented:
The EPA units are not based on time.  It's based on amount of usage of energy.
0
Author Commented:
Is that clearly laid on my monthly statement?  What should I be like looking for ?
0
###### It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
UPS Battery Backup

From novice to tech pro — start learning today.

Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.