iPad

Moving to iPads will reduce the cost of your electric bill

Scott Lowe compares the electricity usage at the endpoint level between desktops, laptops, and iPads.

We all know that iPads are magical and revolutionary devices -- after all, Apple has told us so! Personally, I'm a big fan of the iPad and have somehow managed to talk my wife into letting me upgrade as each new version is released. On my iPads, I've installed tools like LogMeIn Ignition, which I use in conjunction with the LogMeIn service, to control quite a few other systems, including my home desktop, the servers in my lab, and a couple of servers I work on for clients.

This week, let's do a little thought exercise and, for the moment, make the following assumptions:

  • Your company has decided to replace all PCs and laptops with iPads
  • Your company has deployed a VDI environment to support this initiative
  • All hard infrastructure and software costs are exactly equal to what they were when employees had traditional desktops and laptops
  • All licensing issues have been taken care of as well

I realize that these assumptions are a bit out there, but our goal in this article is to compare electricity usage at the endpoint level and nothing else. It's for this reason that we'll make the assumption that all "old" costs equal new costs.

For comparative purposes, we're going to assume that the old desktop/laptop environment consisted of the following types of hardware:

  • 15-inch MacBook Pros (2011)
    • Boot time: 50 watts
    • Typical operation: 12 watts
    • Standby/sleep: 1 watt
    • Source
  • Dell OptiPlex 980 desktops with LCD monitor
    • Boot time: 94 watts
    • Typical operation: 96 watts
    • Standby/sleep: 1 watt
    • Source
  • Dell Latitude XT2 XFR
    • Boot time: 37 watts
    • Typical operational: 30 watts
    • Standby/sleep: 1.5 watts
    • Source
  • iPad
    • Typical operational: 9 watts
    • Standby/sleep: 0.5 watts
    • Multiple sources indicate that the new iPad (2012 model) uses 7 watts of power just for the Retina display, so we'll use 9 watts for calculations

Just from the information in the list, it's really easy to see that the iPads -- even the new iPad, which uses more power than its predecessor, will win this battle. Let's do some math at scale to see what this might mean.

Here are some other assumptions we'll make:

  • Cost of electricity. According to WhiteFence, the 2011 national average commercial price for electricity was 10.11 cents per kilowatt hour, so we'll use that figure in our calculations here.
  • Workday. The workday will be 8 hours long all the time. For the other 16 hours, systems will be in standby or sleeping.
  • iPads will always be plugged in at work and always remain at work. Of course, since people are likely to take them home, this actually means that we'll somewhat overestimate electricity costs, but that's okay.

We'll use the following formula to determine the various costs:

(Watts x Hours Used) / 1000 * Cost per kilowatt-hour = Total Cost per day

The two tables below give you a look at our assumptions and a number of calculations, including how much each device costs to operate per day, per month, and per year.

Model

Op Watts

Standby

$/KWh

Op hrs/day

15 inch MacBook Pro (2011)

12

1

0.1011

8

Dell Optiplex 980 desktop/LCD

96

1

0.1011

8

Dell Latitude XT2 XFR

30

1.5

0.1011

8

iPad 3

9

0.5

0.1011

8

Model

$/day/op

$/day/sleep

$/day/total

$/month

$/year

15 inch MacBook Pro (2011)

0.0097

0.0016

0.0113

0.34

4.13

Dell Optiplex 980 desktop/LCD

0.0776

0.0016

0.0793

2.38

28.93

Dell Latitude XT2 XFR

0.0243

0.0024

0.0267

0.80

9.74

iPad 3

0.0073

0.0008

0.0081

0.24

2.95

As you can see, on per-unit basis, a new iPad can save you a whole lot of money when it comes to comparing power costs between it and a traditional desktop with an LCD monitor. It doesn't fare quite as well against laptops, but there are still savings.

Model

1000 units

iPad savings

15 inch MacBook Pro (2011)

4,132.97

1,180.85

Dell Optiplex 980 desktop/LCD

28,930.78

25,978.66

Dell Latitude XT2 XFR

9,742.00

6,789.88

iPad 3

2,952.12

--

When you look at the desktop savings, that's a good number. Of course, we started by saying that the old and new environment carried exactly equal costs. In most cases, they won't be exactly equal, but potential power savings should be one cost aspect that you consider. It is tough to nail down all of the various assumptions, since things are different from organization to organization, but I highly recommend that you give it a shot!

About

Since 1994, Scott Lowe has been providing technology solutions to a variety of organizations. After spending 10 years in multiple CIO roles, Scott is now an independent consultant, blogger, author, owner of The 1610 Group, and a Senior IT Executive w...

8 comments
aratinga
aratinga

Even if the spreadsheet programs on the iPad are able to do most of the work people do in Excel, the screen size will be a problem for spreadsheet users. So everyone will need a monitor of some sort, which is a major consumer of electricity. Looking around my office, it's true that a lot of people use mostly browsers, email, and word processing. There are a bunch, like me, who use databases and spreadsheets. As much as I love my iPad, I don't think it would be all that great. Although now that there are Citrix clients for iPad, the iPad would make a great low-power remote terminal! Gotta try it on my server!

maj37
maj37

For a company large enough to have 1000 employees using these devices $25k per year is not significant. Also as others have said your comparisons are baloney. No one is replacing desktops or even laptops with tablets, they are adding tablets, so the real electricity cost is an additional $3k for adding the iPads not any savings at all.

CR2011
CR2011

Nice article...really makes you start to think about real TCO. However, wouldn't the cost of licensing and servers of the VDI environment far and away nullify the cost savings of the lower power usage. And the additional servers will certainly bring an increase in the amount of electricity in the datacenter, which, again cancels out any potential savings you would realize. Just my two cents.....

rhonin
rhonin

When an iPad can do the work of a desktop or notebook it might, maybe, possibly could be, but not likely, replace one of these workhorse devices. Till then, it is nice to have a dream.......

pozza8
pozza8

iPad is great - but mostly as a toy. I suspect that 99% of iPADs found in an office are an additional devise and not a replacement. Typically, well often, there is a laptop, a desktop and, now, an iPAD - not to mention all the stuff on charge.

dogknees
dogknees

My bill doesn't cost anything. Certainly my power costs something and the iPad may reduce the amount on the bill, but making the bill cheaper?

Lord Gaga
Lord Gaga

Don't get me wrong, I love my iPad. But I'm not using it to type this comment because I don't like its 'keyboard'. iPads are a poor replacement for a notebook in terms of typical use, cost twice as much as a netbook in a VDI environment, and require far more frequent replacement - its a very short lifecycle. Next to this, the leccy bill is irrelevant, and frankly, given the toxic mix of materials from which its made and the total impossibility of recycling it, any suggestion that it might be green is BS.