A washing machine feels like a steady background cost, but the spending is lopsided in a way that, once you see it, tells you exactly how to spend less. Nearly all of it is one thing, and that one thing is easy to control.
Where the energy goes
The motor that turns the drum, the pumps that move the water, and the spin at the end all draw modest amounts. The heater that warms the water draws far more than the rest combined. So the running cost of a wash is dominated by the temperature you choose, not by the length of the cycle or the spin speed. This is why dropping to a cooler wash is the lever that matters most.
What a wash costs
A cool wash costs only a few pence in energy; a hot one several times that. The water itself adds a little if you are metered. Across a household doing several loads a week, the difference between always washing hot and mostly washing cool adds up to a worthwhile yearly sum. Put your machine's rated consumption, often listed per cycle on its label, through the cost calculator, or work from its wattage and a realistic cycle time, to see your own figure.
Load size matters too
A machine uses broadly similar energy whether half or fully loaded, so running it full rather than part-loaded cuts the cost per item without any change to the wash. Resist the temptation to put a small urgent load on its own; wait until you have a full drum, or use a half-load setting if the machine has a genuine one. Overstuffing is the opposite mistake, as clothes will not clean and you end up rewashing.
Settings that save
Choose the eco programme where there is one, as it uses less despite a longer run, and use the cool everyday cycles for normal laundry. Spin fast to wring out water and shorten any drying. Skip extra rinses unless you need them. None of this requires a new machine; it is simply using the one you have on its thriftier settings, with the temperature dial doing most of the work.