being frugal with hot water — best ways to manage hot water cost

[Wayne&Sam]

Plus it's better for the planet not to use the extra energy. It's only a little bit, but it adds up.

[switz]

We replaced the factory installed six gallon hot water tank system with a Truma "AquaGo comfort" instant on water heater in both the 23D and the Classic. The Truma weighs about 24 pounds less than the tank system and we lost about 50 pounds of stored water weight as well.

To prevent freezing, his models Truma will energize a tiny heater and circulate the water in the heater coils when the ambient temperature drops to 41 degrees or lower. The Truma unit is physically smaller than the removed system as well. It does require a small amount of 12Vdc to run the control circuitry.

[mandolindave]

Originally Posted by HiHoAgRV

That was a question on a Thermodynamics Final exam in my engineering class. It's always better to turn it off. The rate of heat loss is reduced as the water slowly cools. Even with electric heating (basically 100% energy conversion) it's more efficient to heat the cool water than keep it hot.

Nobody would question heating water on the stovetop 2x per day is cheaper than leaving the kettle running all day.

From a "C" Thermo Student...

Then again the water heater doesn't stay on all day.

[Gearheart]

If you're camping in the cool where a space heater is required, the heat loss from the hot water is gain to the trailer. No net loss involved. You pay for it from one pocket or the other. In summer the situation would change as heat transferred from the HW to the trailer is not a blessing.