According to the US Department of Energy web site, "About 90% of the energy used for washing clothes in a conventional top-load washer is for heating the water. There are two ways to reduce the amount of energy used for washing clothes—use less water and use cooler water."
The default setting on my front-loading high efficiency washer "normal cycle" is for "warm". I'm going to try to remember to change it to cold for all but the very dirtiest loads or whites that need it. To do this, I'm going to tape a sticky note over the power button so that it will remind me to change the temperature.
Since this saves gas in the hot water heater, and that costs money, I'm going to code this as a 'win-win'.
Pocket: 7, Planet: 12, Win-Win: 38