Online hot water cost calculator
To put your usage in perspective, consider the following...
One LED light bulb typically use 5Watts electricity per hour and maybe 25Watt per day
Your 2000Watt kettle element boil 4 cups of water for 3 minutes .
Thus, use 100Watt of electricity each time. This is 0.1 Units in kW/h and 3 cents.
Your hot water cylinder has a 3000Watt element that runs over 4 hours per day with a family of 4 to heat 200lt of water. A total usage of 12000watts per day.
This is equal to leaving a 5Watt light bulb on for 100 days continuously.
Also equal to boiling 480 cups of water in your kettle.
And this happens every day of your life! This is the single biggest consumer of electricity in any normal household.
Here is the formula for the experts who like to work it out manually...
To heat one litre of water with one degree Celsius will require 4.180 Joules of energy. Take your delta-temperature of the water times the
amount to be heated.
4180J x 50ᵒCx 180Lt /1000000=Megajoules/3.6=KWh+2kw=Usage
Add your standing heat loss of your hot water cylinder of around 2KWh per day.