Reducing hot water use saves energy because your hot water heater has less work to do. Recent research has shown that on average about 73% of the water used through residential faucets is hot water (DeOreo, et. al. 2001).
Installing new faucet aerators on your kitchen and bathroom sinks is a good idea and can result in some energy savings, particularly if you live in an older house and have older aerators with high flow rates. Faucet aerators are inexpensive (starting at $1 each) and are an inexpensive and effective way to save money in your home.
Source: City of Roanoke, VA
Accessed September 5, 2003, by permission.
If you are looking for further energy savings, don’t let the faucet run continuously while brushing your teeth or washing dishes. If your faucet uses 2.2 gpm, then you can save about 1.6 gallons of hot water for every minute you reduce your faucet use.