You can save money on each washing machine cycle, since the most power is wasted of water heating inside the machine.
So the first thing you need to do is open the manual to your washing machine in find out the difference in energy consumption for a 60 degree Celsius washing cycle and the same program at zero degrees, usually in kilowatts. Multiply this value by the 1 kilowatt fee imposed by your electric company, and you get the first value.
Now find out how much water the machine uses during the main cycle (i.e. before rinsing), usually in litres, and multiply it by the fee for 1 litre of hot running water, or the cost of gas to heat 1 litre, if you have a water heater. This information is also available in the heater manual.
If the cost of power to heat up water inside the machine is higher than getting the same amount of hot water, then you could save money by not using the built-in heater and supplying hot water into the machine.
To do that, first put the laundry inside the machine. Then add detergent right inside the tumble. Select 0 as the temperature, meaning cold wash.
Now use a shower to pour in the water through the detergent compartment, if your washing machine is in the bathroom, or a hose if it is in the kitchen. You may attach a funnel for easier fit.
Insert one end of the hose to the detergent compartment, open water and adjust it to the desired temperature, and put the hose under the running water. Water starts to get into the machine.
Mark the usual level your machine pours water in automatic mode, and fill it to approximately the same level.
Start the washing programme. The machine starts the cycle. You don’t need to supervise it, since rinsing water will come from the cold water supply. You should also know, that some
modern washing machines are connected to both hot and cold water, and they don’t require any manual filling.