Which is more economical? Keeping a storage water heater on or turning it on once a day to shower then off?

Question

It is a 40g water heater. I always used to turn it off at the breaker switch, keeping it off until 5-10 min before showering, but now someone says the draw of electricity to heat up all that water is more expensive than keeping it on all day. Which is more economical?

Answer 1

If you turn it off it turns into a bacteria stew.  When your hot water heater dies look int o replacing it with a hot water on demand system that does not store any hot water.

Answer 2

Turning it off is more economical but not by much, if it is a fairly modern heater with reasonable insulation. You would likely save more energy by turning the thermostat down to ~120F if you haven't done so already. It is thermodynamically impossible for it to take more energy to reheat the water than what you saved while it was off.

Answer 3

40 gallons seems like an awful lot of water to heat just to take a bath.  I would think that keeping that size continually heated would be cheaper than re-heating it again and again.

I would suggest using a smaller tank, say 20 gallons, but the folks to ask would be the electric utility company who provides the electricity to you.

Answer 4

Depends. If you have to heat your house, then the water heater left on is good as most water heaters are over 80% efficient, so as it loses heat to the air in your house, then the house heater doesn't come on.

I use an integrated heater system that heats the house and water together.  The heater is 95+% efficient.  Because of snow build up and bad weather, passive solar works well, but solar convection system are problematic. So I heat a large amount of my space with huge south facing windows that have shades to reduce heat loss at night.

Answer 5

cheaper to turn it off, absolutely. in fact, you should investigate tankless water heater if that is the only load. even more energy efficient.

Answer 6

I really think you'll have a marginal savings by turning it off.  Most water heaters are pretty well insulated and don't use much energy if you're not using them.

Answer 7

Great answers. Am agreeing with some here that turning off

the WH will save one $.  However, MasterPy's response is an eyebrow lifter, water that has been sitting in the WH after WH has been turned off ...is bacteria stew, ewwww. Yahuwceph, I think you should have asked whether anyone would shower with bacteria stew. C'mon, admit it, you are enjoying that stew....Yummm