How electricity is measured

Have you ever asked yourself, what is energy measured in? The primary way electricity consumption is measured is with the unit “watt-hour”.

Lighting and common household appliances such as air conditioning units, computers and toasters are all products requiring electricity to function.

A watt (w) is a measure of this electric power and each of these household products should be marked with a watt rating to reflect their usage. Most common household appliances owned by consumers include a compliance badge, which is used to indicate the amount of electrical power that the particular product requires to function correctly.

To put this into perspective, a light bulb could have a 40-watt rating, an average toaster could have a 600-watt rating and an air conditioner could have a 4000-watt rating. Multiplying the watt – or the unit of energy required – by the duration of its usage will offer the amount of total electricity consumed.

The standard measure of electricity consumption is the amount of watts expended over the period of one hour, which is also known as a watt-hour. This means if a 40 watt light bulb is turned on for one hour, it will use 40 watt-hours of electricity.

When people receive an electricity bill, it will record the number of kilowatt-hours (kWh) consumed during that period by the household. A kilowatt-hour is 1000 watt-hours, which means using a 4000 watt air-conditioner for one hour will consume 4 kWh of electricity.

This total consumption is what is used to calculate the pricing of an energy bill, which is delivered to customers quarterly or every three months.

How electricity is measured

A kilowatt-hour (kWh) is the amount of electricity produced or consumed in one hour.

In Australia, the typical daily usage of a common household is around 17,000 watt-hours of power. To calculate this from watts to kWh, it would equal around 17 kilowatt-hours. 

Watt (W)
= 1 watt

40 W
A 40 W lightbulb uses 40 watts of electricity.

Kilowatt (kW)
= 1000 watts

2 kW
The typical solar panel used by an Australian household can produce up to 2 kW of electricity.

Megawatt (MW)
= 1 million watts

30 MW
The Cullerin Range wind farm north of Canberra – recently sold by Origin Energy – is capable of producing 30 MW of electricity. 

Gigawatt (GW)
= 1000 million watts

3 GW
Origin’s Eraring Power Station is Australia’s largest power station and it has a total capacity of around 3 GW, 

To compare how the energy usage of your home shapes up with other similar households in your local area, visit Energy Made Easy


  1. on electricity consumption benchmarks on residential customers  bills – December 2014_0.PDF

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