Home Improvement → Re: Electric Water Heater Timer Worth It?

Yes, but with the timer, your water will cool-down (during the day?) and you'll still need to heat it all up to normal temperature when the timer turns-on. The electricity for that re-heat is not free.

That was always the conventional thinking on the subject. However, newer, better quality water heater tanks (eg, those with multiple inches of foam insulation) have very little standby heat loss.

This sounds very similar to the thinking that a/c and heat thermostat set-backs do not save money because the house eventually will return to a living condition temp.

If you keep the temperature at full during the day, some of the heat used to make up for losses is itself lost, plus at a higher temperature difference the heat loss is greater. You'll always save energy by only heating the water right before you need it rather than holding it hot. The downside is the time it takes for the water to heat.