The dirty secret about laundry:
When you use a washing machine, about 90 percent of the energy goes to
water heating.
Changing your washing machine settings to warm wash and cold rinse (or better yet, cold for both) can save money and energy on water heating.
But how much? Washing your clothes on the warm setting instead of hot, for instance,
could cut your energy use in half, according to the Department of Energy. Clothes will still get so fresh and so clean, and they won't fade or shrink as quickly, either.