A major contributor to electricity usage is standby energy consumption. Most households contain appliances which consume electricity even when they are not operational, this is referred to as standby energy consumption, and can amount to over 10% of total electricity used in a typical home. Appliances and equipment with standby mode include televisions, computers, home entertainment systems, Wi-Fi/internet modems, split system conditioners, battery chargers, white goods, and any other equipment which consumes power while not performing its primary function.
These sorts of things add to your energy consumption even when you’re not home. An energy audit will be able to tell you how much standby power is being generated from each of your appliances.
Household behaviour, demographic characteristics, appliances installed by occupants and attitudes are other major contributors to energy consumption.
Reverse cycle air conditioners and high-watt lights (especially downlights) are all positively correlated with higher consumption recordings.
Building efficiency can also attribute to larger consumption rates.
These factors can greatly affect electricity usage consumption. As many of these are quite variable from day to day, no one single contributor can be responsible for the complete difference in variating consumption.
You maybe interested in Ways to Reduce your Energy Invoices for further information.