Does it Help to Turn off Water Heater?
Most recent answer: 08/04/2015
- Michael Cookson (age 48)
Burnham, Maine USA
I think your mom is right. The amount of heat that the electric heater will need to supply is about equal to the extra thermal energy that flows out in the hot water plus the heat that leaks out to the room from the heater. If you assume that the water use is fixed, then the only thing that would change is the heat leak. If the heater is kept a little les hot when it won't be used for a long time, then the heat leak will be reduced a bit.
There can be problems with growth of bacteria in tanks that are kept warm but not hot, so before switching to your mom's system you might check with somebody who does this sort of work professionally.
To really save energy, you could switch to a heat-pump water heater. because these heat up more slowly, you have to leave them on all the time. The little extra heat leak is not important compared to the very large efficiency improvement.
Mike W.
(published on 08/04/2015)