Consumption is simply the amount of electricity any appliance uses during its operation.

How is it measured?

Electricity is measured in units called Watts.  1,000 Watts = 1 Killowatt, and if you use 1 Killowatt of electricity in an hour you have consumed 1 Killowatt-Hour or 1 unit of electricity.  If you look at your bill it will show how many units of electricity you have consumed during that particular billing period.  Your Electricity Tarrif will explain the cost per unit, so the bill will be the number of units x the cost per unit.  There is normally an additional fixed charge added on and VAT at the appropriate rate.

Your electricity provider will measure the power you use and this is shown on your bill as a number of Killowatt-hours or Kwh.  This information is obtained from your electricity meter.  The reading from your previous bill is subtracted from the meter reading for your latest bill to give the number on Kwh's (often referred to as units) which have been used during the billing period.

Any appliance will consume a stated number of Watts and the consumption is calculated by multiplying the Watts by the Hours of Use and dividing by 1000 to give the figure in Kwh or Units.

Appliance power in watts x number of hours in use / 1000  =  Units consumed

How do I know how many Watts my appliance uses?

All appliances will have a Rating Plate attached, usually somewhere at the back, but fridges will sometimes have this inside or on the inner surface of the door.

The rating plate will identify the appliance type and manufacturers code number and will show the power rating in Watts.  Sometimes it will also have the serial number of the machine printed or stuck on.

The rating plate is usually silver in colour, like a piece of bare metal, and the figures are often embossed on.  It can be tricky to find once the appliance is installed, so have a look before it's fitted.   Sometimes the information is also contained in the instruction and installation information.

For a guide to appliance consumption you can check out our chart here.