Hi
Is the purpose to reduce the energy consumption? Is the heater electric or gas? In either situation, you could possibly reduce the energy use by shutting it off. If you use a timer, and if the heater is electric, then make sure that you have a system that will handle the amperage load of the elements. Usually 1500 watts each, or about 13 amps at 120v or half of that at 220v.
Consider that you must heat the water up again when you want to use it.
A good method to reduce "standby energy loss" is to ADD INSULATION TO THE HEATER. There are standard size blankets available to add to the heater. Or, if you are handy, and you should be handy according to "Red Green" (only if your not handsome - "If the women don't find you handsome, they should at least find you handy." ), then you can add insulation to the tank, and then attach it with your favorite adhesive tape, or baling twine, or whatever.
Lots is better, of insulation.
Another good technique is to lower the water temperature. However, if you have a dishwasher, then you need it higher. Hand washing and showering can use very low temperature water, about 105F (if you have a big enough tank so that you do not depend on a higher temperature water mixed with cold to supply some of your required hot water during high demand times).
Good luck whatever you do.
Alex
