Have you ever wondered how much power your iPad consumes as compared to corporate server?  What are some of the world’s most power hungry devices?  First let’s introduce the concepts of power and what it means.  Electrical power is measured in watts, W, a unit of power. Electrical current is measured in amps, A, the rate at which it flows.  Sometimes you might see a rating of KVA.  This is a measurement of Volts time Amperes in thousands; 100 KVA = 100,000 volt amps.  Typically you will find this rating on an UPS (uninterruptable power supply) or battery backup.

What is a Watt?

Power is a measure of the rate at which energy flows, and in electrical systems it is measured in watts (W). Watts are basically tell you how fast the electrons are speeding down the highway.  A 60-watt lightbulb will consume electricity at a rate of 60 watts. A laborer working through the day will put out 75 watts of power. A medium-sized car might consume 100,000 watts.  A small gasoline generator puts out 2,000 watts; the Vermont Yankee nuclear power plant puts out 650 megawatts, or 650,000,000 watts (1).
So just what are some of the Worlds most power hungry devices?  Listed below are someelectricormal day and at work followed by devices that make the internet work.  This list shows the number of watts or power each device uses.


Typical hand held devices and their power usage

  • iPad Air (A7) – almost 12W (2)
  • iPad 4 (A6X)  – almost 8W (2)
  • Microsoft XBox – 150W (3)
  • Dell PowerEdge R910 – 940W (4)
  • Cisco 12000 Series Router –  2441W (5)

Now let’s take a look at some of the everyday appliances you use every day in your house and what all of this energy usage means to you.

Table data cited below is from the Electrical Safety Council (1).

Domestic Portable Appliance        

Amps Used

Watts Used

Laptop <0.5 65 – 100
Mobile phone charger <0.5 <12
Kettle 13 3000
Satellite TV box <0.5 30
Printer <0.5 50
Radio <0.5 40
Radiator 8.5 2000
DVD player <0.5 28
Hair dryer 10.0 2200
Landline cordless telephone charger <0.5 10
Computer monitor <0.5 100
Desktop computer 3.0 700
Television 42″ HD 0.5 120
Games console 0.86 <200
Washing machine 10 2200
Toaster 9.0 2000
Tumble dryer 11.0 2500
Dishwasher 10.0 2200
Iron 12.5 2800
Microwave 4.5 1000
Vacuum cleaner 9.0 2000
Radiator (oil filled) 13.0 3000


As you can see your iPad, iPhone or other hand held device uses less energy than your gaming console or the DVD player.  Even though these devices use less energy they need to be charged up once in a while in order to keep them running.  Fortunately your hand held iPad does not need to be plugged in all the time like a router on the internet.  Even the world’s most power hungry devices need to have their energy use payed for and the cost for running them is something to be worried about.  Your handheld device does have a much lower cost but how long does it take to recharge the battery?

Why does my iPad take ages to charge?

Are you using the correct charger?  Not all chargers are the same.  That’s why there’s such a wide range of price discrepancy between different chargers. Recharging your iPad with a 1Amp charger (suitable for an iPhone) will charge slower than if you used the correct 2.1Amp charger. Using a higher AMP rating charger won’t necessarily charge your device any quicker either, and can be quite dangerous.  This limitation is due to the fact that some devices like the iPad limit the current pulled from the charger.  Some chargers feature smart technology that detects the appropriate current flow your device needs.  Most batteries like to be charged at the same rate that they discharge.

1)  http://www2.buildinggreen.com/blogs/what-watt-anyway-understanding-energy-and-power-metrics
2)  http://www.anandtech.com/show/7460/apple-ipad-air-review/3
3)  http://www.forbes.com/sites/christopherhelman/2013/09/07/how-much-energy-does-your-iphone-and-other-devices-use-and-what-to-do-about-it/
4)  http://www.dell.com/downloads/global/products/pedge/en/R910_4P_E7-4870_1100W_Energy_Star_Data_Sheet.pdf
5)  http://www.cisco.com/c/en/us/td/docs/ios/12_0s/feature/guide/12spower.html