IMO, about the most energy efficient and water efficient way to clean clothes is a wringer washer and clotheslines. My current washer is a 60 year old Maytag that was $5 at an auction. You can adjust agitating time and water use infinitely, to your own needs. My usual routine is to wash the next load in the rinse water from the last load, starting with the light clothes. Others wash all the loads in the same water, then rinse them all in the same water, but our stuff is generally to dirty for that to work well (we have 3 kids under 8, and we are building a homestead. Dirt is our constant companion.
Then, dry on the line. In freezing weather, I dry stuff that is needed soon on racks inside, the rest on the line outside. A pair of the really cheap fit-everyone winter gloves under a pair of rubber dish gloves does a fair job of allowing clothes hanging without frostbit fingers.