About 80% to 85% of the energy used for washing clothes is for heating the water. You can reduce the amount of energy used for washing clothes by either using less water or by using cooler water.
Laundry Tips From Energy.gov
Wash only full loads. A very full load means that less water used and less energy used per item of clothing. If you’re laundry a little load, use the suitable water-level setting.
Wash your clothes in cold water. Hot water has got to be heated and you’re paying for that service. Unless you’re dealing with oily stains, the warm or cold water setting machine will generally do a good job of cleaning your clothes. Switching your temperature setting from hot to warm can cut a load’s energy use in half, and switching from warm to cold can reduce the energy consumption even more.
Dry towels and heavier cottons in a separate load from lighter-weight clothes.
Don’t over-dry your clothes. If your machine has a moisture sensor, use it.
Clean the lint screen in the dryer after every load to improve air circulation and prevent fire hazards.
Periodically, use the long nozzle tip on your vacuum cleaner to remove the lint that collects below the lint screen in the lint screen slot of your clothes dryer.
Use the cool-down cycle to allow the clothes to finish drying with the heat remaining in the dryer.
Periodically inspect your dryer vent to ensure it is not blocked. This will save energy and may prevent a fire. Manufacturers recommend using rigid venting material — not plastic vents that may collapse and cause blockages.
Consider air-drying clothes on clothes lines or drying racks. If you can, hang your clothes to dry instead of sucking down energy in the dryer. An average dryer run eats about $0.25 worth of electricity.