Approximately 90% of the energy used to wash your laundry is used to heat the water. Warm and cold water can do a good job in cleaning your clothes. If you have oily stains on your clothes, opt for the hot. Other than that, you can save about 50% of the energy normally used to wash with hot water if you choose to go warm or cold.
Also, when drying your clothes try to dry the towels and heavier cottons in a separate load from the lighter-weight clothes. Drying will be more efficient, especially if you remember to clean the lint filter in the dryer after every load. It will improve air circulation.